Handle mouseEventsRequireAlt option changes in mouse mode

Co-authored-by: Daniel Imms <Tyriar@users.noreply.github.com>

src/browser/CoreBrowserTerminal.ts

@@ -623,6 +623,7 @@ export class CoreBrowserTerminal extends CoreTerminal implements ITerminal {
       this.element.classList.add('enable-mouse-events');
     } else {
       this._selectionService.enable();
+      this.element.classList.remove('enable-mouse-events');
     }
 
     if (this.options.screenReaderMode) {

src/browser/services/MouseService.test.ts

@@ -7,6 +7,7 @@ import { MouseService } from 'browser/services/MouseService';
 import { MouseStateService } from 'common/services/MouseStateService';
 import { CoreMouseAction, CoreMouseButton } from 'common/Types';
 import { IBufferService, ICoreService, ILogService, IOptionsService } from 'common/services/Services';
+import { OptionsService } from 'common/services/OptionsService';
 import { MockCoreBrowserService, MockRenderService, MockSelectionService } from 'browser/TestUtils.test';
 
 function toBytes(s: string | undefined): number[] {
@@ -42,6 +43,36 @@ const logService: ILogService = {
   error: () => {}
 } as any;
 
+class TestSelectionService extends MockSelectionService {
+  public enableCount = 0;
+  public disableCount = 0;
+
+  public override enable(): void {
+    this.enableCount++;
+  }
+
+  public override disable(): void {
+    this.disableCount++;
+  }
+
+  public override shouldForceSelection(): boolean {
+    return false;
+  }
+}
+
+function createTestMouseTargetElement(): HTMLElement {
+  const classes = new Set<string>();
+  return {
+    classList: {
+      add: (className: string) => classes.add(className),
+      remove: (className: string) => classes.delete(className),
+      contains: (className: string) => classes.has(className)
+    },
+    addEventListener: () => {},
+    removeEventListener: () => {}
+  } as any;
+}
+
 describe('MouseService _triggerMouseEvent', () => {
   let mouseService: MouseService;
   let mouseStateService: MouseStateService;
@@ -211,3 +242,52 @@ describe('MouseService _triggerMouseEvent', () => {
     reports = [];
   });
 });
+
+describe('MouseService mouseEventsRequireAlt', () => {
+  it('should update selection state and cursor class when toggled while mouse events are active', () => {
+    const mouseStateService = new MouseStateService();
+    const optionsService = new OptionsService({});
+    const selectionService = new TestSelectionService();
+    const mouseService = new MouseService(
+      new MockRenderService(),
+      {
+        getMouseReportCoords: (_ev: MouseEvent, _el: HTMLElement) => ({ col: 0, row: 0, x: 0, y: 0 })
+      } as any,
+      mouseStateService,
+      {
+        triggerDataEvent: () => {},
+        triggerBinaryEvent: () => {},
+        decPrivateModes: { applicationCursorKeys: false }
+      } as any,
+      bufferService,
+      optionsService,
+      selectionService,
+      logService,
+      new MockCoreBrowserService()
+    );
+    const element = createTestMouseTargetElement();
+    const screenElement = createTestMouseTargetElement();
+    const document = {
+      addEventListener: () => {},
+      removeEventListener: () => {}
+    } as any;
+
+    mouseService.bindMouse({
+      element,
+      screenElement,
+      document
+    }, disposable => disposable, () => {});
+
+    mouseStateService.activeProtocol = 'ANY';
+    assert.isTrue(element.classList.contains('enable-mouse-events'));
+    assert.equal(selectionService.disableCount, 1);
+
+    optionsService.options.mouseEventsRequireAlt = true;
+    assert.isFalse(element.classList.contains('enable-mouse-events'));
+    assert.equal(selectionService.enableCount, 2);
+
+    optionsService.options.mouseEventsRequireAlt = false;
+    assert.isTrue(element.classList.contains('enable-mouse-events'));
+    assert.equal(selectionService.disableCount, 2);
+  });
+});

src/browser/services/MouseService.ts

@@ -66,6 +66,9 @@ export class MouseService implements IMouseService {
     register(this._mouseStateService.onProtocolChange(events => {
       this._handleProtocolChange(ctx, eventListeners, events);
     }));
+    register(this._optionsService.onSpecificOptionChange('mouseEventsRequireAlt', () => {
+      this._syncMouseModeState(element);
+    }));
     // force initial onProtocolChange so we dont miss early mouse requests
     this._mouseStateService.activeProtocol = this._mouseStateService.activeProtocol;
 
@@ -360,6 +363,21 @@ export class MouseService implements IMouseService {
     this._touchScrollAccumulator = 0;
   }
 
+  private _syncMouseModeState(element: HTMLElement): void {
+    if (this._mouseStateService.areMouseEventsActive) {
+      if (this._optionsService.rawOptions.mouseEventsRequireAlt) {
+        element.classList.remove('enable-mouse-events');
+        this._selectionService.enable();
+      } else {
+        element.classList.add('enable-mouse-events');
+        this._selectionService.disable();
+      }
+    } else {
+      element.classList.remove('enable-mouse-events');
+      this._selectionService.enable();
+    }
+  }
+
   private _handleProtocolChange(ctx: IMouseBindContext, eventListeners: Record<'mouseup' | 'wheel' | 'mousedrag' | 'mousemove', EventListener>, events: CoreMouseEventType): void {
     const { element, document } = ctx.target;
     const { requestedEvents } = ctx;
@@ -368,17 +386,10 @@ export class MouseService implements IMouseService {
       if (this._optionsService.rawOptions.logLevel === 'debug') {
         this._logService.debug('Binding to mouse events:', this._explainEvents(events));
       }
-      if (this._optionsService.rawOptions.mouseEventsRequireAlt) {
-        this._selectionService.enable();
-      } else {
-        element.classList.add('enable-mouse-events');
-        this._selectionService.disable();
-      }
     } else {
       this._logService.debug('Unbinding from mouse events.');
-      element.classList.remove('enable-mouse-events');
-      this._selectionService.enable();
     }
+    this._syncMouseModeState(element);
 
     // add/remove handlers from requestedEvents
     if (!(events & CoreMouseEventType.MOVE)) {