feat: implemented select all notes feature.

public/config.json

@@ -35,6 +35,7 @@
             "play": "space",
             "undo": "ctrl+z",
             "redo": "ctrl+shift+z",
+            "select_all": "ctrl+a",
             "copy": "ctrl+c",
             "cut": "ctrl+x",
             "paste": "ctrl+v",

src/core/config/ConfigManager.ts

@@ -41,6 +41,7 @@ interface AppConfig {
       play: string;
       undo: string;
       redo: string;
+      select_all: string;
       copy: string;
       cut: string;
       paste: string;
@@ -195,6 +196,7 @@ export class ConfigManager {
             play: 'space',
             undo: 'ctrl+z',
             redo: 'ctrl+shift+z',
+            select_all: 'ctrl+a',
             copy: 'ctrl+c',
             cut: 'ctrl+x',
             paste: 'ctrl+v', 

src/hooks/useGlobalKeyboardHandler.ts

@@ -4,6 +4,7 @@ import { handleCopyOperation, handlePasteOperation } from '../util/copyPasteUtil
 import { saveProject } from '../util/saveUtil';
 import { ConfigManager } from '../core/config/ConfigManager';
 import { useProjectStore } from '../stores/projectStore';
+import { selectAllNotesInActiveRegion } from '../util/selectionUtil';
 
 /**
  * Global keyboard handler for copy/paste, undo/redo, play/pause, and save operations
@@ -56,6 +57,7 @@ export const useGlobalKeyboardHandler = () => {
       const redoShortcut = configManager.get('hotkeys.main.redo') as string;
       const copyShortcut = configManager.get('hotkeys.main.copy') as string;
       const pasteShortcut = configManager.get('hotkeys.main.paste') as string;
+      const selectAllShortcut = configManager.get('hotkeys.main.select_all') as string;
       const playShortcut = configManager.get('hotkeys.main.play') as string;
       const saveShortcut = configManager.get('hotkeys.main.save') as string;
 
@@ -109,6 +111,13 @@ export const useGlobalKeyboardHandler = () => {
         return;
       }
 
+      // Check for select-all-notes shortcut (only when piano roll is open)
+      if (selectAllShortcut && matchesKeyboardShortcut(event, selectAllShortcut)) {
+        event.preventDefault();
+        selectAllNotesInActiveRegion();
+        return;
+      }
+
       // Check for play/pause shortcut
       if (playShortcut && matchesKeyboardShortcut(event, playShortcut)) {
         event.preventDefault();

src/util/selectionUtil.ts

@@ -0,0 +1,56 @@
+import { KGCore } from '../core/KGCore';
+import { useProjectStore } from '../stores/projectStore';
+import { KGMidiRegion } from '../core/region/KGMidiRegion';
+import { KGTrack } from '../core/track/KGTrack';
+import { KGMidiNote } from '../core/midi/KGMidiNote';
+
+/**
+ * Select all notes in the active region if the piano roll is visible.
+ * Logs the count and region id on success.
+ * Returns true if selection was performed; false otherwise.
+ */
+export const selectAllNotesInActiveRegion = (): boolean => {
+  const { showPianoRoll, activeRegionId, updateTrack } = useProjectStore.getState();
+  if (!showPianoRoll || !activeRegionId) {
+    return false;
+  }
+
+  try {
+    const core = KGCore.instance();
+    const project = core.getCurrentProject();
+    const tracks = project.getTracks();
+
+    let parentTrack: KGTrack | null = null;
+    let activeRegion: KGMidiRegion | null = null;
+
+    for (const track of tracks) {
+      const region = track.getRegions().find(r => r.getId() === activeRegionId);
+      if (region && region instanceof KGMidiRegion) {
+        parentTrack = track as KGTrack;
+        activeRegion = region as KGMidiRegion;
+        break;
+      }
+    }
+
+    if (!activeRegion || !parentTrack) {
+      return false;
+    }
+
+    // Clear previous selection and select all notes in the region
+    core.clearSelectedItems();
+    const notes: KGMidiNote[] = activeRegion.getNotes();
+    notes.forEach((n: KGMidiNote) => n.select());
+    core.addSelectedItems(notes);
+
+    // Update track to persist selection state in model/UI
+    updateTrack(parentTrack);
+
+    console.log(`Selected all notes: count=${notes.length}, regionId=${activeRegionId}`);
+    return true;
+  } catch (error) {
+    console.error('Select all notes failed:', error);
+    return false;
+  }
+};
+
+