Introduce file picker and GUI configuration with enhancements.

- Add visual file picker for GUI with toggle support.
- Introduce `GUIConfig` class for loading GUI settings from configuration file.
- Refactor window initialization to support dynamic sizing based on configuration.
- Add macOS-specific handling for fullscreen behavior.
- Improve header inclusion order and minor code cleanup.

.idea/workspace.xml

@@ -33,12 +33,58 @@
     </configurations>
   </component>
   <component name="ChangeListManager">
-    <list default="true" id="e1fe3ab0-3650-4fca-8664-a247d5dfa457" name="Changes" comment="Refactor code for consistency and enhanced functionality.&#10;&#10;- Normalize path handling for buffer operations, supporting tilde expansion and absolute paths.&#10;- Introduce `DisplayNameFor` to uniquely resolve buffer display names, minimizing filename clashes.&#10;- Add new commands: `ShowWorkingDirectory` and `ChangeWorkingDirectory`.&#10;- Refine keybindings and enhance existing commands for improved command flow.&#10;- Adjust GUI and terminal renderers to display total line counts alongside filenames.&#10;- Update coding style to align with project guidelines.">
+    <list default="true" id="e1fe3ab0-3650-4fca-8664-a247d5dfa457" name="Changes" comment="Add horizontal scrolling support and refactor mouse click handling in GUI.&#10;&#10;- Introduce horizontal scrolling with column offset synchronization in GUI.&#10;- Refactor mouse click handling for improved accuracy and viewport alignment.&#10;- Enhance tab expansion and cursor rendering logic for better user experience.&#10;- Replace redundant variable declarations in `Buffer` for cleaner code.">
+      <change afterPath="$PROJECT_DIR$/GUIConfig.cc" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/GUIConfig.h" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.icns" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_128x128.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_128x128@2x.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_16x16.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_16x16@2x.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_256x256.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_256x256@2x.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_32x32.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_32x32@2x.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_512x512.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.iconset/icon_512x512@2x.png" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/kge.png" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/Buffer.cc" beforeDir="false" afterPath="$PROJECT_DIR$/Buffer.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/Buffer.h" beforeDir="false" afterPath="$PROJECT_DIR$/Buffer.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/CMakeLists.txt" beforeDir="false" afterPath="$PROJECT_DIR$/CMakeLists.txt" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/Command.cc" beforeDir="false" afterPath="$PROJECT_DIR$/Command.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/Command.h" beforeDir="false" afterPath="$PROJECT_DIR$/Command.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/Editor.cc" beforeDir="false" afterPath="$PROJECT_DIR$/Editor.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/Editor.h" beforeDir="false" afterPath="$PROJECT_DIR$/Editor.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/Frontend.h" beforeDir="false" afterPath="$PROJECT_DIR$/Frontend.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/GUIFrontend.cc" beforeDir="false" afterPath="$PROJECT_DIR$/GUIFrontend.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/GUIFrontend.h" beforeDir="false" afterPath="$PROJECT_DIR$/GUIFrontend.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/GUIInputHandler.cc" beforeDir="false" afterPath="$PROJECT_DIR$/GUIInputHandler.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/GUIInputHandler.h" beforeDir="false" afterPath="$PROJECT_DIR$/GUIInputHandler.h" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/GUIRenderer.cc" beforeDir="false" afterPath="$PROJECT_DIR$/GUIRenderer.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/GUIRenderer.h" beforeDir="false" afterPath="$PROJECT_DIR$/GUIRenderer.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/GapBuffer.cc" beforeDir="false" afterPath="$PROJECT_DIR$/GapBuffer.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/GapBuffer.h" beforeDir="false" afterPath="$PROJECT_DIR$/GapBuffer.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/InputHandler.h" beforeDir="false" afterPath="$PROJECT_DIR$/InputHandler.h" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/KKeymap.cc" beforeDir="false" afterPath="$PROJECT_DIR$/KKeymap.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/KKeymap.h" beforeDir="false" afterPath="$PROJECT_DIR$/KKeymap.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/PieceTable.h" beforeDir="false" afterPath="$PROJECT_DIR$/PieceTable.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/TerminalFrontend.cc" beforeDir="false" afterPath="$PROJECT_DIR$/TerminalFrontend.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/TerminalFrontend.h" beforeDir="false" afterPath="$PROJECT_DIR$/TerminalFrontend.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/TerminalInputHandler.cc" beforeDir="false" afterPath="$PROJECT_DIR$/TerminalInputHandler.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/TerminalInputHandler.h" beforeDir="false" afterPath="$PROJECT_DIR$/TerminalInputHandler.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/TerminalRenderer.cc" beforeDir="false" afterPath="$PROJECT_DIR$/TerminalRenderer.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/TestFrontend.cc" beforeDir="false" afterPath="$PROJECT_DIR$/TestFrontend.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/TestInputHandler.h" beforeDir="false" afterPath="$PROJECT_DIR$/TestInputHandler.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/TestRenderer.cc" beforeDir="false" afterPath="$PROJECT_DIR$/TestRenderer.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/TestRenderer.h" beforeDir="false" afterPath="$PROJECT_DIR$/TestRenderer.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/UndoNode.h" beforeDir="false" afterPath="$PROJECT_DIR$/UndoNode.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/UndoSystem.cc" beforeDir="false" afterPath="$PROJECT_DIR$/UndoSystem.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/UndoSystem.h" beforeDir="false" afterPath="$PROJECT_DIR$/UndoSystem.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/UndoTree.h" beforeDir="false" afterPath="$PROJECT_DIR$/UndoTree.h" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/cmake/Info.plist.in" beforeDir="false" afterPath="$PROJECT_DIR$/cmake/Info.plist.in" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/main.cc" beforeDir="false" afterPath="$PROJECT_DIR$/main.cc" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/test_undo.cc" beforeDir="false" afterPath="$PROJECT_DIR$/test_undo.cc" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -59,15 +105,6 @@
   <component name="HighlightingSettingsPerFile">
     <setting file="mock:///AIAssistantSnippet.." root0="SKIP_HIGHLIGHTING" />
     <setting file="mock:///AIAssistantSnippet.." root0="SKIP_HIGHLIGHTING" />
-    <setting file="mock:///AIAssistantSnippet.." root0="SKIP_HIGHLIGHTING" />
-    <setting file="mock:///dummy.cpp" root0="SKIP_HIGHLIGHTING" />
-    <setting file="mock:///dummy.cpp" root0="SKIP_HIGHLIGHTING" />
-    <setting file="mock:///dummy.cpp" root0="SKIP_HIGHLIGHTING" />
-    <setting file="mock:///dummy.cpp" root0="SKIP_HIGHLIGHTING" />
-    <setting file="mock:///dummy.cpp" root0="SKIP_HIGHLIGHTING" />
-    <setting file="mock:///dummy.cpp" root0="SKIP_HIGHLIGHTING" />
-    <setting file="mock:///dummy.cpp" root0="SKIP_HIGHLIGHTING" />
-    <setting file="mock:///dummy.cpp" root0="SKIP_HIGHLIGHTING" />
   </component>
   <component name="OptimizeOnSaveOptions">
     <option name="myRunOnSave" value="true" />
@@ -134,6 +171,11 @@
     </key>
   </component>
   <component name="RunManager" selected="CMake Application.kge">
+    <configuration default="true" type="CLionExternalRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true">
+      <method v="2">
+        <option name="CLION.EXTERNAL.BUILD" enabled="true" />
+      </method>
+    </configuration>
     <configuration name="imgui" type="CMakeRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" PASS_PARENT_ENVS_2="true" PROJECT_NAME="kte" TARGET_NAME="imgui" CONFIG_NAME="Debug">
       <method v="2">
         <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
@@ -170,7 +212,7 @@
       <workItem from="1764539556448" duration="156000" />
       <workItem from="1764539725338" duration="1075000" />
       <workItem from="1764542392763" duration="3512000" />
-      <workItem from="1764548345516" duration="3453000" />
+      <workItem from="1764548345516" duration="7941000" />
     </task>
     <task id="LOCAL-00001" summary="Add undo/redo infrastructure and buffer management additions.">
       <option name="closed" value="true" />
@@ -252,7 +294,15 @@
       <option name="project" value="LOCAL" />
       <updated>1764550164829</updated>
     </task>
-    <option name="localTasksCounter" value="11" />
+    <task id="LOCAL-00011" summary="Add horizontal scrolling support and refactor mouse click handling in GUI.&#10;&#10;- Introduce horizontal scrolling with column offset synchronization in GUI.&#10;- Refactor mouse click handling for improved accuracy and viewport alignment.&#10;- Enhance tab expansion and cursor rendering logic for better user experience.&#10;- Replace redundant variable declarations in `Buffer` for cleaner code.">
+      <option name="closed" value="true" />
+      <created>1764551986561</created>
+      <option name="number" value="00011" />
+      <option name="presentableId" value="LOCAL-00011" />
+      <option name="project" value="LOCAL" />
+      <updated>1764551986561</updated>
+    </task>
+    <option name="localTasksCounter" value="12" />
     <servers />
   </component>
   <component name="TypeScriptGeneratedFilesManager">
@@ -276,7 +326,8 @@
     <MESSAGE value="Add man pages for `kge` and `kte` with installation targets in CMake.&#10;&#10;- Introduce `docs/kge.1` and `docs/kte.1` man pages covering usage, options, keybindings, and examples.&#10;- Update `CMakeLists.txt` to install man pages under `${CMAKE_INSTALL_MANDIR}/man1`.&#10;- Ensure `kge` man page installation is conditional on GUI being built." />
     <MESSAGE value="Add GUI initialization updates and improve navigation commands.&#10;&#10;- Implement terminal detachment for GUI mode to enable terminal closure post-launch.&#10;- Add `+N` support for opening files at specific line numbers and refine cursor positioning.&#10;- Introduce `JumpToLine` command for direct navigation by line number.&#10;- Enhance mouse wheel handling for line-wise scrolling." />
     <MESSAGE value="Refactor code for consistency and enhanced functionality.&#10;&#10;- Normalize path handling for buffer operations, supporting tilde expansion and absolute paths.&#10;- Introduce `DisplayNameFor` to uniquely resolve buffer display names, minimizing filename clashes.&#10;- Add new commands: `ShowWorkingDirectory` and `ChangeWorkingDirectory`.&#10;- Refine keybindings and enhance existing commands for improved command flow.&#10;- Adjust GUI and terminal renderers to display total line counts alongside filenames.&#10;- Update coding style to align with project guidelines." />
-    <option name="LAST_COMMIT_MESSAGE" value="Refactor code for consistency and enhanced functionality.&#10;&#10;- Normalize path handling for buffer operations, supporting tilde expansion and absolute paths.&#10;- Introduce `DisplayNameFor` to uniquely resolve buffer display names, minimizing filename clashes.&#10;- Add new commands: `ShowWorkingDirectory` and `ChangeWorkingDirectory`.&#10;- Refine keybindings and enhance existing commands for improved command flow.&#10;- Adjust GUI and terminal renderers to display total line counts alongside filenames.&#10;- Update coding style to align with project guidelines." />
+    <MESSAGE value="Add horizontal scrolling support and refactor mouse click handling in GUI.&#10;&#10;- Introduce horizontal scrolling with column offset synchronization in GUI.&#10;- Refactor mouse click handling for improved accuracy and viewport alignment.&#10;- Enhance tab expansion and cursor rendering logic for better user experience.&#10;- Replace redundant variable declarations in `Buffer` for cleaner code." />
+    <option name="LAST_COMMIT_MESSAGE" value="Add horizontal scrolling support and refactor mouse click handling in GUI.&#10;&#10;- Introduce horizontal scrolling with column offset synchronization in GUI.&#10;- Refactor mouse click handling for improved accuracy and viewport alignment.&#10;- Enhance tab expansion and cursor rendering logic for better user experience.&#10;- Replace redundant variable declarations in `Buffer` for cleaner code." />
   </component>
   <component name="XSLT-Support.FileAssociations.UIState">
     <expand />

Buffer.cc

@@ -1,12 +1,12 @@
-#include "Buffer.h"
-#include "UndoSystem.h"
-#include "UndoTree.h"
-
 #include <fstream>
 #include <sstream>
 #include <filesystem>
 #include <cstdlib>
 
+#include "Buffer.h"
+#include "UndoSystem.h"
+#include "UndoTree.h"
+
 
 Buffer::Buffer()
 {

Buffer.h

@@ -12,6 +12,7 @@
 #include "AppendBuffer.h"
 #include "UndoSystem.h"
 
+
 class Buffer {
 public:
 	Buffer();

CMakeLists.txt

@@ -128,6 +128,8 @@ endif ()
 if (${BUILD_GUI})
     target_sources(kte PRIVATE
             Font.h
+            GUIConfig.cc
+            GUIConfig.h
             GUIRenderer.cc
             GUIRenderer.h
             GUIInputHandler.cc
@@ -142,6 +144,8 @@ if (${BUILD_GUI})
             main.cc
             ${COMMON_SOURCES}
             ${COMMON_HEADERS}
+            GUIConfig.cc
+            GUIConfig.h
             GUIRenderer.cc
             GUIRenderer.h
             GUIInputHandler.cc
@@ -153,6 +157,15 @@ if (${BUILD_GUI})
 
     # On macOS, build kge as a proper .app bundle
     if (APPLE)
+        # Define the icon file
+        set(MACOSX_BUNDLE_ICON_FILE kge.icns)
+        set(kge_ICON "${CMAKE_CURRENT_SOURCE_DIR}/${MACOSX_BUNDLE_ICON_FILE}")
+
+        # Add icon to the target sources and mark it as a resource
+        target_sources(kge PRIVATE ${kge_ICON})
+        set_source_files_properties(${kge_ICON} PROPERTIES
+                MACOSX_PACKAGE_LOCATION Resources)
+
         # Configure Info.plist with version and identifiers
         set(KGE_BUNDLE_ID "dev.wntrmute.kge")
         configure_file(
@@ -164,6 +177,7 @@ if (${BUILD_GUI})
                 MACOSX_BUNDLE TRUE
                 MACOSX_BUNDLE_GUI_IDENTIFIER ${KGE_BUNDLE_ID}
                 MACOSX_BUNDLE_BUNDLE_NAME "kge"
+                MACOSX_BUNDLE_ICON_FILE ${MACOSX_BUNDLE_ICON_FILE}
                 MACOSX_BUNDLE_INFO_PLIST "${CMAKE_CURRENT_BINARY_DIR}/kge-Info.plist")
 
         install(TARGETS kge

Command.cc

@@ -6,14 +6,13 @@
 #include "Editor.h"
 #include "Buffer.h"
 #include "UndoSystem.h"
-// Note: Command layer must remain UI-agnostic. Do not include frontend/IO headers here.
 
 
 // Keep buffer viewport offsets so that the cursor stays within the visible
 // window based on the editor's current dimensions. The bottom row is reserved
 // for the status line.
 static std::size_t
-compute_render_x(const std::string &line, std::size_t curx, std::size_t tabw)
+compute_render_x(const std::string &line, const std::size_t curx, const std::size_t tabw)
 {
 	std::size_t rx = 0;
 	for (std::size_t i = 0; i < curx && i < line.size(); ++i) {
@@ -474,7 +473,7 @@ cmd_change_working_directory_start(CommandContext &ctx)
 {
 	std::string initial;
 	try {
-		initial = std::filesystem::current_path().string();
+		initial = std::filesystem::current_path().string() + "/";
 	} catch (...) {
 		initial.clear();
 	}
@@ -677,6 +676,30 @@ cmd_open_file_start(CommandContext &ctx)
 }
 
 
+// GUI: toggle visual file picker (no-op in terminal; renderer will consume flag)
+static bool
+cmd_visual_file_picker_toggle(CommandContext &ctx)
+{
+	// Toggle visibility
+	bool show = !ctx.editor.FilePickerVisible();
+	ctx.editor.SetFilePickerVisible(show);
+	if (show) {
+		// Initialize directory to current working directory if empty
+		if (ctx.editor.FilePickerDir().empty()) {
+			try {
+				ctx.editor.SetFilePickerDir(std::filesystem::current_path().string());
+			} catch (...) {
+				ctx.editor.SetFilePickerDir(".");
+			}
+		}
+		ctx.editor.SetStatus("Open File (visual)");
+	} else {
+		ctx.editor.SetStatus("Closed file picker");
+	}
+	return true;
+}
+
+
 static bool
 cmd_jump_to_line_start(CommandContext &ctx)
 {
@@ -2630,6 +2653,11 @@ InstallDefaultCommands()
 		CommandId::MarkAllAndJumpEnd, "mark-all-jump-end", "Set mark at beginning and jump to end",
 		cmd_mark_all_and_jump_end
 	});
+	// GUI
+	CommandRegistry::Register({
+		CommandId::VisualFilePickerToggle, "file-picker-toggle", "Toggle visual file picker",
+		cmd_visual_file_picker_toggle
+	});
 	// Working directory
 	CommandRegistry::Register({
 		CommandId::ShowWorkingDirectory, "show-working-directory", "Show current working directory",

Command.h

@@ -24,6 +24,8 @@ enum class CommandId {
 	KPrefix, // show "C-k _" prompt in status when entering k-command
 	FindStart, // begin incremental search (placeholder)
 	OpenFileStart, // begin open-file prompt
+	// GUI: visual file picker
+	VisualFilePickerToggle,
 	// Buffers
 	BufferSwitchStart, // begin buffer switch prompt
 	BufferClose,

Editor.cc

@@ -1,9 +1,9 @@
-#include "Editor.h"
-
 #include <algorithm>
 #include <utility>
 #include <filesystem>
 
+#include "Editor.h"
+
 
 Editor::Editor() = default;
 

Editor.h

@@ -441,6 +441,31 @@ public:
 		return buffers_;
 	}
 
+
+	// --- GUI: Visual File Picker state ---
+	void SetFilePickerVisible(bool on)
+	{
+		file_picker_visible_ = on;
+	}
+
+
+	[[nodiscard]] bool FilePickerVisible() const
+	{
+		return file_picker_visible_;
+	}
+
+
+	void SetFilePickerDir(const std::string &path)
+	{
+		file_picker_dir_ = path;
+	}
+
+
+	[[nodiscard]] const std::string &FilePickerDir() const
+	{
+		return file_picker_dir_;
+	}
+
 private:
 	std::size_t rows_ = 0, cols_ = 0;
 	int mode_         = 0;
@@ -478,6 +503,10 @@ private:
 	std::string prompt_label_;
 	std::string prompt_text_;
 	std::string pending_overwrite_path_;
+
+	// GUI-only state (safe no-op in terminal builds)
+	bool file_picker_visible_ = false;
+	std::string file_picker_dir_;
 };
 
 #endif // KTE_EDITOR_H

Frontend.h

@@ -4,8 +4,6 @@
 #ifndef KTE_FRONTEND_H
 #define KTE_FRONTEND_H
 
-#include <memory>
-
 
 class Editor;
 class InputHandler;

GUIConfig.cc

@@ -0,0 +1,107 @@
+#include <cstdlib>
+#include <cstring>
+#include <fstream>
+#include <sstream>
+#include <algorithm>
+
+#include "GUIConfig.h"
+
+
+static void
+trim(std::string &s)
+{
+	auto not_space = [](int ch) {
+		return !std::isspace(ch);
+	};
+	s.erase(s.begin(), std::find_if(s.begin(), s.end(), not_space));
+	s.erase(std::find_if(s.rbegin(), s.rend(), not_space).base(), s.end());
+}
+
+
+static std::string
+default_config_path()
+{
+	const char *home = std::getenv("HOME");
+	if (!home || !*home)
+		return std::string();
+	std::string path(home);
+	path += "/.config/kte/kge.ini";
+	return path;
+}
+
+
+GUIConfig
+GUIConfig::Load()
+{
+	GUIConfig cfg; // defaults already set
+	std::string path = default_config_path();
+	if (!path.empty()) {
+		cfg.LoadFromFile(path);
+	}
+	return cfg;
+}
+
+
+bool
+GUIConfig::LoadFromFile(const std::string &path)
+{
+	std::ifstream in(path);
+	if (!in.good())
+		return false;
+
+	std::string line;
+	while (std::getline(in, line)) {
+		// Remove comments starting with '#' or ';'
+		auto hash = line.find('#');
+		if (hash != std::string::npos)
+			line.erase(hash);
+		auto sc = line.find("//");
+		if (sc != std::string::npos)
+			line.erase(sc);
+		// Basic key=value
+		auto eq = line.find('=');
+		if (eq == std::string::npos)
+			continue;
+		std::string key = line.substr(0, eq);
+		std::string val = line.substr(eq + 1);
+		trim(key);
+		trim(val);
+		// Strip trailing semicolon
+		if (!val.empty() && val.back() == ';') {
+			val.pop_back();
+			trim(val);
+		}
+
+		// Lowercase key
+		std::transform(key.begin(), key.end(), key.begin(), [](unsigned char c) {
+			return (char) std::tolower(c);
+		});
+
+		if (key == "fullscreen") {
+			fullscreen = (val == "1" || val == "true" || val == "on" || val == "yes");
+		} else if (key == "columns" || key == "cols") {
+			int v = columns;
+			try {
+				v = std::stoi(val);
+			} catch (...) {}
+			if (v > 0)
+				columns = v;
+		} else if (key == "rows") {
+			int v = rows;
+			try {
+				v = std::stoi(val);
+			} catch (...) {}
+			if (v > 0)
+				rows = v;
+		} else if (key == "font_size" || key == "fontsize") {
+			float v = font_size;
+			try {
+				v = std::stof(val);
+			} catch (...) {}
+			if (v > 0.0f)
+				font_size = v;
+		}
+	}
+
+	return true;
+}

GUIConfig.h

@@ -0,0 +1,27 @@
+/*
+ * GUIConfig - loads simple GUI configuration from $HOME/.config/kte/kge.ini
+ */
+#ifndef KTE_GUI_CONFIG_H
+#define KTE_GUI_CONFIG_H
+
+#include <string>
+
+#ifndef KTE_FONT_SIZE
+#define KTE_FONT_SIZE 16.0f
+#endif
+
+class GUIConfig {
+public:
+	bool fullscreen = false;
+	int columns     = 80;
+	int rows        = 42;
+	float font_size = (float) KTE_FONT_SIZE;
+
+	// Load from default path: $HOME/.config/kte/kge.ini
+	static GUIConfig Load();
+
+	// Load from explicit path. Returns true if file existed and was parsed.
+	bool LoadFromFile(const std::string &path);
+};
+
+#endif // KTE_GUI_CONFIG_H

GUIFrontend.cc

@@ -1,18 +1,25 @@
-#include <SDL.h>
-#include <SDL_opengl.h>
-
-#include <imgui.h>
-#include <backends/imgui_impl_sdl2.h>
-#include <backends/imgui_impl_opengl3.h>
 #include <cstdio>
 #include <string>
 #include <cstring>
 #include <cstdlib>
+#include <algorithm>
+
+#include <SDL.h>
+#include <SDL_opengl.h>
+#include <imgui.h>
+#include <backends/imgui_impl_sdl2.h>
+#include <backends/imgui_impl_opengl3.h>
 
 #include "Editor.h"
 #include "Command.h"
 #include "GUIFrontend.h"
 #include "Font.h" // embedded default font (DefaultFontRegular)
+#include "GUIConfig.h"
+
+
+#ifndef KTE_FONT_SIZE
+#define KTE_FONT_SIZE 16.0f
+#endif
 
 static const char *kGlslVersion = "#version 150"; // GL 3.2 core (macOS compatible)
 
@@ -24,6 +31,9 @@ GUIFrontend::Init(Editor &ed)
 		return false;
 	}
 
+	// Load GUI configuration (fullscreen, columns/rows, font size)
+	const auto [fullscreen, columns, rows, font_size] = GUIConfig::Load();
+
 	// GL attributes for core profile
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, 0);
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
@@ -33,14 +43,56 @@ GUIFrontend::Init(Editor &ed)
 	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
 	SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 8);
 
+	// Compute desired window size from config
+	Uint32 win_flags = SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI;
+
+	if (fullscreen) {
+		// "Fullscreen": fill the usable bounds of the primary display.
+		// On macOS, do NOT use true fullscreen so the menu/status bar remains visible.
+		SDL_Rect usable{};
+		if (SDL_GetDisplayUsableBounds(0, &usable) == 0) {
+			width_  = usable.w;
+			height_ = usable.h;
+		}
+#if !defined(__APPLE__)
+		// Non-macOS: desktop fullscreen uses the current display resolution.
+		win_flags |= SDL_WINDOW_FULLSCREEN_DESKTOP;
+#endif
+	} else {
+		// Windowed: width = columns * font_size, height = (rows * 2) * font_size
+		int w = static_cast<int>(columns * font_size);
+		int h = static_cast<int>((rows * 2) * font_size);
+
+		// As a safety, clamp to display usable bounds if retrievable
+		SDL_Rect usable{};
+		if (SDL_GetDisplayUsableBounds(0, &usable) == 0) {
+			w = std::min(w, usable.w);
+			h = std::min(h, usable.h);
+		}
+		width_  = std::max(320, w);
+		height_ = std::max(200, h);
+	}
+
 	window_ = SDL_CreateWindow(
-		"kte",
+		"kge - kyle's text editor " KTE_VERSION_STR,
 		SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
 		width_, height_,
-		SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI);
+		win_flags);
 	if (!window_)
 		return false;
 
+#if defined(__APPLE__)
+	// macOS: when "fullscreen" is requested, position the window at the
+	// top-left of the usable display area to mimic fullscreen while keeping
+	// the system menu bar visible.
+	if (fullscreen) {
+		SDL_Rect usable{};
+		if (SDL_GetDisplayUsableBounds(0, &usable) == 0) {
+			SDL_SetWindowPosition(window_, usable.x, usable.y);
+		}
+	}
+#endif
+
 	gl_ctx_ = SDL_GL_CreateContext(window_);
 	if (!gl_ctx_)
 		return false;
@@ -64,11 +116,23 @@ GUIFrontend::Init(Editor &ed)
 	width_  = w;
 	height_ = h;
 
-	// Initialize GUI font from embedded default
-#ifndef KTE_FONT_SIZE
-#define KTE_FONT_SIZE 16.0f
+#if defined(__APPLE__)
+	// Workaround: On macOS Retina when starting maximized, we sometimes get a
+	// subtle input vs draw alignment mismatch until the first manual resize.
+	// Nudge the window size by 1px and back to trigger a proper internal
+	// recomputation, without visible impact.
+	if (w > 1 && h > 1) {
+		SDL_SetWindowSize(window_, w - 1, h - 1);
+		SDL_SetWindowSize(window_, w, h);
+		// Update cached size in case backend reports immediately
+		SDL_GetWindowSize(window_, &w, &h);
+		width_  = w;
+		height_ = h;
+	}
 #endif
-	LoadGuiFont_(nullptr, (float) KTE_FONT_SIZE);
+
+	// Initialize GUI font from embedded default (use configured size or compiled default)
+	LoadGuiFont_(nullptr, (float) font_size);
 
 	return true;
 }

GUIFrontend.h

@@ -8,6 +8,7 @@
 #include "GUIInputHandler.h"
 #include "GUIRenderer.h"
 
+
 struct SDL_Window;
 typedef void *SDL_GLContext;
 

GUIInputHandler.cc

@@ -1,7 +1,8 @@
-#include <SDL.h>
 #include <cstdio>
 #include <ncurses.h>
 
+#include <SDL.h>
+
 #include "GUIInputHandler.h"
 #include "KKeymap.h"
 

GUIInputHandler.h

@@ -4,11 +4,12 @@
 #ifndef KTE_GUI_INPUT_HANDLER_H
 #define KTE_GUI_INPUT_HANDLER_H
 
-#include <queue>
 #include <mutex>
+#include <queue>
 
 #include "InputHandler.h"
 
+
 union SDL_Event; // fwd decl to avoid including SDL here (SDL defines SDL_Event as a union)
 
 class GUIInputHandler final : public InputHandler {

GUIRenderer.cc

@@ -1,29 +1,44 @@
-#include "GUIRenderer.h"
-
-#include "Editor.h"
-#include "Buffer.h"
-#include "Command.h"
+#include <cmath>
+#include <cstdio>
+#include <filesystem>
+#include <limits>
+#include <string>
 
 #include <imgui.h>
-#include <cstdio>
-#include <string>
-#include <filesystem>
-#include <cmath>
-#include <limits>
+
+#include "GUIRenderer.h"
+#include "Buffer.h"
+#include "Command.h"
+#include "Editor.h"
+
 
 // Version string expected to be provided by build system as KTE_VERSION_STR
 #ifndef KTE_VERSION_STR
 #  define KTE_VERSION_STR "dev"
 #endif
 
+// ImGui compatibility: some bundled ImGui versions (or builds without docking)
+// don't define ImGuiWindowFlags_NoDocking. Treat it as 0 in that case.
+#ifndef ImGuiWindowFlags_NoDocking
+#  define ImGuiWindowFlags_NoDocking 0
+#endif
+
 
 void
 GUIRenderer::Draw(Editor &ed)
 {
 	// Make the editor window occupy the entire GUI container/viewport
 	ImGuiViewport *vp = ImGui::GetMainViewport();
-	ImGui::SetNextWindowPos(vp->Pos);
-	ImGui::SetNextWindowSize(vp->Size);
+	// On HiDPI/Retina, snap to integer pixels to prevent any draw vs hit-test
+	// mismatches that can appear on the very first maximized frame.
+	ImVec2 main_pos = vp->Pos;
+	ImVec2 main_sz  = vp->Size;
+	main_pos.x      = std::floor(main_pos.x + 0.5f);
+	main_pos.y      = std::floor(main_pos.y + 0.5f);
+	main_sz.x       = std::floor(main_sz.x + 0.5f);
+	main_sz.y       = std::floor(main_sz.y + 0.5f);
+	ImGui::SetNextWindowPos(main_pos);
+	ImGui::SetNextWindowSize(main_sz);
 
 	ImGuiWindowFlags flags = ImGuiWindowFlags_NoTitleBar
 	                         | ImGuiWindowFlags_NoResize
@@ -379,4 +394,153 @@ GUIRenderer::Draw(Editor &ed)
 
 	ImGui::End();
 	ImGui::PopStyleVar(3);
+
+	// --- Visual File Picker overlay (GUI only) ---
+	if (ed.FilePickerVisible()) {
+		// Centered popup-style window that always fits within the current viewport
+		ImGuiViewport *vp2 = ImGui::GetMainViewport();
+
+		// Desired size, min size, and margins
+		const ImVec2 want(800.0f, 500.0f);
+		const ImVec2 min_sz(240.0f, 160.0f);
+		const float margin = 20.0f; // space from viewport edges
+
+		// Compute the maximum allowed size (viewport minus margins) and make sure it's not negative
+		ImVec2 max_sz(std::max(32.0f, vp2->Size.x - 2.0f * margin),
+		              std::max(32.0f, vp2->Size.y - 2.0f * margin));
+
+		// Clamp desired size to [min_sz, max_sz]
+		ImVec2 size(std::min(want.x, max_sz.x), std::min(want.y, max_sz.y));
+		size.x = std::max(size.x, std::min(min_sz.x, max_sz.x));
+		size.y = std::max(size.y, std::min(min_sz.y, max_sz.y));
+
+		// Center within the viewport using the final size
+		ImVec2 pos(vp2->Pos.x + std::max(margin, (vp2->Size.x - size.x) * 0.5f),
+		           vp2->Pos.y + std::max(margin, (vp2->Size.y - size.y) * 0.5f));
+
+		// On HiDPI displays (macOS Retina), ensure integer pixel alignment to avoid
+		// potential hit-test vs draw mismatches from sub-pixel positions.
+		pos.x  = std::floor(pos.x + 0.5f);
+		pos.y  = std::floor(pos.y + 0.5f);
+		size.x = std::floor(size.x + 0.5f);
+		size.y = std::floor(size.y + 0.5f);
+
+		ImGui::SetNextWindowPos(pos, ImGuiCond_Always);
+		ImGui::SetNextWindowSize(size, ImGuiCond_Always);
+		ImGuiWindowFlags wflags = ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoCollapse |
+		                          ImGuiWindowFlags_NoDocking;
+		bool open = true;
+		if (ImGui::Begin("File Picker", &open, wflags)) {
+			// Current directory
+			std::string curdir = ed.FilePickerDir();
+			if (curdir.empty()) {
+				try {
+					curdir = std::filesystem::current_path().string();
+				} catch (...) {
+					curdir = ".";
+				}
+				ed.SetFilePickerDir(curdir);
+			}
+			ImGui::TextUnformatted(curdir.c_str());
+			ImGui::SameLine();
+			if (ImGui::Button("Up")) {
+				try {
+					std::filesystem::path p(curdir);
+					if (p.has_parent_path()) {
+						ed.SetFilePickerDir(p.parent_path().string());
+					}
+				} catch (...) {}
+			}
+			ImGui::SameLine();
+			if (ImGui::Button("Close")) {
+				ed.SetFilePickerVisible(false);
+			}
+
+			ImGui::Separator();
+
+			// Header
+			ImGui::TextUnformatted("Name");
+			ImGui::Separator();
+
+			// Scrollable list
+			ImGui::BeginChild("picker-list", ImVec2(0, 0), true);
+
+			// Build entries: directories first then files, alphabetical
+			struct Entry {
+				std::string name;
+				std::filesystem::path path;
+				bool is_dir;
+			};
+			std::vector<Entry> entries;
+			entries.reserve(256);
+			// Optional parent entry
+			try {
+				std::filesystem::path base(curdir);
+				std::error_code ec;
+				for (auto it = std::filesystem::directory_iterator(base, ec);
+				     !ec && it != std::filesystem::directory_iterator(); it.increment(ec)) {
+					const auto &p = it->path();
+					std::string nm;
+					try {
+						nm = p.filename().string();
+					} catch (...) {
+						continue;
+					}
+					if (nm == "." || nm == "..")
+						continue;
+					bool is_dir = false;
+					std::error_code ec2;
+					is_dir = it->is_directory(ec2);
+					entries.push_back({nm, p, is_dir});
+				}
+			} catch (...) {
+				// ignore listing errors; show empty
+			}
+			std::sort(entries.begin(), entries.end(), [](const Entry &a, const Entry &b) {
+				if (a.is_dir != b.is_dir)
+					return a.is_dir && !b.is_dir;
+				return a.name < b.name;
+			});
+
+			// Draw rows
+			int idx = 0;
+			for (const auto &e: entries) {
+				ImGui::PushID(idx++); // ensure unique/stable IDs even if names repeat
+				std::string label;
+				label.reserve(e.name.size() + 4);
+				if (e.is_dir)
+					label += "[";
+				label += e.name;
+				if (e.is_dir)
+					label += "]";
+
+				// Render selectable row
+				ImGui::Selectable(label.c_str(), false, ImGuiSelectableFlags_AllowDoubleClick);
+
+				// Activate based strictly on hover + mouse, to avoid any off-by-one due to click routing
+				if (ImGui::IsItemHovered()) {
+					if (e.is_dir && ImGui::IsMouseDoubleClicked(ImGuiMouseButton_Left)) {
+						// Enter directory on double-click
+						ed.SetFilePickerDir(e.path.string());
+					} else if (!e.is_dir && ImGui::IsMouseClicked(ImGuiMouseButton_Left)) {
+						// Open file on single click
+						std::string err;
+						if (!ed.OpenFile(e.path.string(), err)) {
+							ed.SetStatus(std::string("open: ") + err);
+						} else {
+							ed.SetStatus(std::string("Opened: ") + e.name);
+						}
+						ed.SetFilePickerVisible(false);
+					}
+				}
+				ImGui::PopID();
+			}
+
+			ImGui::EndChild();
+		}
+		ImGui::End();
+		if (!open) {
+			ed.SetFilePickerVisible(false);
+		}
+	}
 }

GUIRenderer.h

@@ -6,7 +6,7 @@
 
 #include "Renderer.h"
 
-class GUIRenderer : public Renderer {
+class GUIRenderer final : public Renderer {
 public:
 	GUIRenderer() = default;
 

GapBuffer.cc

@@ -1,9 +1,10 @@
-#include "GapBuffer.h"
-
 #include <algorithm>
 #include <cassert>
 #include <cstring>
 
+#include "GapBuffer.h"
+
+
 GapBuffer::GapBuffer() = default;
 
 

GapBuffer.h

@@ -6,6 +6,7 @@
 
 #include <cstddef>
 
+
 class GapBuffer {
 public:
 	GapBuffer();

InputHandler.h

@@ -8,6 +8,7 @@
 
 #include "Command.h"
 
+
 // Result of translating raw input into an editor command.
 struct MappedInput {
 	bool hasCommand = false;

KKeymap.cc

@@ -1,9 +1,9 @@
-#include "KKeymap.h"
-
 #include <iostream>
 #include <ncurses.h>
 #include <ostream>
 
+#include "KKeymap.h"
+
 
 auto
 KLookupKCommand(const int ascii_key, const bool ctrl, CommandId &out) -> bool
@@ -83,6 +83,9 @@ KLookupKCommand(const int ascii_key, const bool ctrl, CommandId &out) -> bool
 	case 'u':
 		out = CommandId::Undo;
 		return true;
+	case 'v':
+		out = CommandId::VisualFilePickerToggle;
+		return true;
 	case 'w':
 		out = CommandId::ShowWorkingDirectory;
 		return true;

KKeymap.h

@@ -6,6 +6,7 @@
 
 #include "Command.h"
 
+
 // Lookup the command to execute after a C-k prefix.
 // Parameters:
 //  - ascii_key: ASCII code of the key, preferably lowercased if it's a letter.

PieceTable.h

@@ -8,6 +8,7 @@
 #include <string>
 #include <vector>
 
+
 class PieceTable {
 public:
 	PieceTable();

TerminalFrontend.cc

@@ -1,10 +1,10 @@
-#include <unistd.h>
-#include <termios.h>
 #include <ncurses.h>
+#include <termios.h>
+#include <unistd.h>
 
-#include "Editor.h"
-#include "Command.h"
 #include "TerminalFrontend.h"
+#include "Command.h"
+#include "Editor.h"
 
 
 bool

TerminalFrontend.h

@@ -4,10 +4,11 @@
 #ifndef KTE_TERMINAL_FRONTEND_H
 #define KTE_TERMINAL_FRONTEND_H
 
+#include <termios.h>
+
 #include "Frontend.h"
 #include "TerminalInputHandler.h"
 #include "TerminalRenderer.h"
-#include <termios.h>
 
 
 class TerminalFrontend final : public Frontend {

TerminalInputHandler.cc

@@ -1,8 +1,8 @@
-#include <ncurses.h>
 #include <cstdio>
+#include <ncurses.h>
 
-#include "KKeymap.h"
 #include "TerminalInputHandler.h"
+#include "KKeymap.h"
 
 namespace {
 constexpr int

TerminalInputHandler.h

@@ -4,8 +4,6 @@
 #ifndef KTE_TERMINAL_INPUT_HANDLER_H
 #define KTE_TERMINAL_INPUT_HANDLER_H
 
-#include <cstdint>
-
 #include "InputHandler.h"
 
 

TerminalRenderer.cc

@@ -1,19 +1,19 @@
-#include "TerminalRenderer.h"
-
-#include <ncurses.h>
-#include <cstdio>
-#include <string>
 #include <algorithm>
+#include <cstdio>
 #include <filesystem>
+#include <ncurses.h>
+#include <string>
 
-#include "Editor.h"
+#include "TerminalRenderer.h"
 #include "Buffer.h"
+#include "Editor.h"
 
 // Version string expected to be provided by build system as KTE_VERSION_STR
 #ifndef KTE_VERSION_STR
 #  define KTE_VERSION_STR "dev"
 #endif
 
+
 TerminalRenderer::TerminalRenderer() = default;
 
 TerminalRenderer::~TerminalRenderer() = default;

TestFrontend.cc

@@ -1,7 +1,6 @@
 #include "TestFrontend.h"
-#include "Editor.h"
 #include "Command.h"
-#include <iostream>
+#include "Editor.h"
 
 
 bool

TestInputHandler.h

@@ -4,11 +4,12 @@
 #ifndef KTE_TEST_INPUT_HANDLER_H
 #define KTE_TEST_INPUT_HANDLER_H
 
-#include "InputHandler.h"
 #include <queue>
 
+#include "InputHandler.h"
 
-class TestInputHandler : public InputHandler {
+
+class TestInputHandler final : public InputHandler {
 public:
 	TestInputHandler() = default;
 
@@ -21,7 +22,7 @@ public:
 	void QueueText(const std::string &text);
 
 
-	bool IsEmpty() const
+	[[nodiscard]] bool IsEmpty() const
 	{
 		return queue_.empty();
 	}

TestRenderer.cc

@@ -1,5 +1,4 @@
 #include "TestRenderer.h"
-#include "Editor.h"
 
 
 void

TestRenderer.h

@@ -4,11 +4,12 @@
 #ifndef KTE_TEST_RENDERER_H
 #define KTE_TEST_RENDERER_H
 
-#include "Renderer.h"
 #include <cstddef>
 
+#include "Renderer.h"
 
-class TestRenderer : public Renderer {
+
+class TestRenderer final : public Renderer {
 public:
 	TestRenderer() = default;
 
@@ -17,7 +18,7 @@ public:
 	void Draw(Editor &ed) override;
 
 
-	std::size_t GetDrawCount() const
+	[[nodiscard]] std::size_t GetDrawCount() const
 	{
 		return draw_count_;
 	}

UndoNode.h

@@ -1,8 +1,6 @@
 #ifndef KTE_UNDONODE_H
 #define KTE_UNDONODE_H
 
-#include <cstddef>
-#include <cstdint>
 #include <string>
 
 

UndoSystem.cc

@@ -16,7 +16,7 @@ UndoSystem::Begin(UndoType type)
 		if (type == UndoType::Delete) {
 			// Support batching both forward deletes (DeleteChar) and backspace (prepend case)
 			// Forward delete: cursor stays at anchor col; expected == col
-			std::size_t anchor = static_cast<std::size_t>(tree_.pending->col);
+			const auto anchor = static_cast<std::size_t>(tree_.pending->col);
 			if (anchor + tree_.pending->text.size() == static_cast<std::size_t>(col)) {
 				pending_prepend_ = false;
 				return; // keep batching forward delete

UndoSystem.h

@@ -2,8 +2,10 @@
 #define KTE_UNDOSYSTEM_H
 
 #include <string_view>
+
 #include "UndoTree.h"
 
+
 class Buffer;
 
 class UndoSystem {
@@ -39,7 +41,6 @@ private:
 
 	void update_dirty_flag();
 
-private:
 	Buffer *buf_;
 	UndoTree &tree_;
 	// Internal hint for Delete batching: whether next Append() should prepend

UndoTree.h

@@ -2,7 +2,7 @@
 #define KTE_UNDOTREE_H
 
 #include "UndoNode.h"
-#include <memory>
+
 
 struct UndoTree {
 	UndoNode *root    = nullptr; // first edit ever

cmake/Info.plist.in

@@ -6,6 +6,8 @@
     <string>en</string>
     <key>CFBundleExecutable</key>
     <string>kge</string>
+    <key>CFBundleIconFile</key>
+    <string>@MACOSX_BUNDLE_ICON_FILE@</string>
     <key>CFBundleIdentifier</key>
     <string>@KGE_BUNDLE_ID@</string>
     <key>CFBundleInfoDictionaryVersion</key>
@@ -23,4 +25,4 @@
     <key>NSHighResolutionCapable</key>
     <true/>
 </dict>
-</plist>
+</plist>

main.cc

@@ -1,15 +1,15 @@
+#include <cctype>
+#include <cstdio>
+#include <getopt.h>
 #include <iostream>
 #include <memory>
-#include <string>
-#include <cctype>
-#include <unistd.h>
-#include <getopt.h>
 #include <signal.h>
-#include <cstdio>
+#include <string>
+#include <unistd.h>
 #include <sys/stat.h>
 
-#include "Editor.h"
 #include "Command.h"
+#include "Editor.h"
 #include "Frontend.h"
 #include "TerminalFrontend.h"
 
@@ -22,6 +22,7 @@
 #  define KTE_VERSION_STR "devel"
 #endif
 
+
 static void
 PrintUsage(const char *prog)
 {

test_undo.cc

@@ -1,10 +1,11 @@
-#include <iostream>
 #include <cassert>
 #include <fstream>
+#include <iostream>
+
+#include "Buffer.h"
+#include "Command.h"
 #include "Editor.h"
 #include "TestFrontend.h"
-#include "Command.h"
-#include "Buffer.h"
 
 
 int