Hover on keyboard modifier should trigger instantly

src/vs/editor/contrib/hover/browser/contentHoverController.ts

@@ -17,7 +17,7 @@ import { IKeybindingService } from '../../../../platform/keybinding/common/keybi
 import { ResultKind } from '../../../../platform/keybinding/common/keybindingResolver.js';
 import { HoverVerbosityAction } from '../../../common/languages.js';
 import { RunOnceScheduler } from '../../../../base/common/async.js';
-import { isMousePositionWithinElement, shouldShowHover } from './hoverUtils.js';
+import { isMousePositionWithinElement, shouldShowHover, isTriggerModifierPressed } from './hoverUtils.js';
 import { ContentHoverWidgetWrapper } from './contentHoverWidgetWrapper.js';
 import './hover.css';
 import { Emitter } from '../../../../base/common/event.js';
@@ -266,12 +266,18 @@ export class ContentHoverController extends Disposable implements IEditorContrib
 	}
 
 	private _onKeyDown(e: IKeyboardEvent): void {
-		if (this._ignoreMouseEvents) {
+		if (this._ignoreMouseEvents || !this._contentWidget) {
 			return;
 		}
-		if (!this._contentWidget) {
-			return;
+
+		if (this._hoverSettings.enabled === 'onKeyboardModifier'
+			&& isTriggerModifierPressed(this._editor.getOption(EditorOption.multiCursorModifier), e)
+			&& this._mouseMoveEvent) {
+			if (!this._contentWidget.isVisible) {
+				this._contentWidget.showsOrWillShow(this._mouseMoveEvent);
+			}
 		}
+
 		const isPotentialKeyboardShortcut = this._isPotentialKeyboardShortcut(e);
 		const isModifierKeyPressed = isModifierKey(e.keyCode);
 		if (isPotentialKeyboardShortcut || isModifierKeyPressed) {

src/vs/editor/contrib/hover/browser/glyphHoverController.ts

@@ -12,7 +12,7 @@ import { IEditorContribution, IScrollEvent } from '../../../common/editorCommon.
 import { IInstantiationService } from '../../../../platform/instantiation/common/instantiation.js';
 import { IHoverWidget } from './hoverTypes.js';
 import { RunOnceScheduler } from '../../../../base/common/async.js';
-import { isMousePositionWithinElement, shouldShowHover } from './hoverUtils.js';
+import { isMousePositionWithinElement, isTriggerModifierPressed, shouldShowHover } from './hoverUtils.js';
 import './hover.css';
 import { GlyphHoverWidget } from './glyphHoverWidget.js';
 
@@ -206,6 +206,15 @@ export class GlyphHoverController extends Disposable implements IEditorContribut
 		if (!this._editor.hasModel()) {
 			return;
 		}
+
+		if (this._hoverSettings.enabled === 'onKeyboardModifier'
+			&& isTriggerModifierPressed(this._editor.getOption(EditorOption.multiCursorModifier), e)
+			&& this._mouseMoveEvent) {
+			if (this._tryShowHoverWidget(this._mouseMoveEvent)) {
+				return;
+			}
+		}
+
 		if (isModifierKey(e.keyCode)) {
 			// Do not hide hover when a modifier key is pressed
 			return;

src/vs/editor/contrib/hover/browser/hoverUtils.ts

@@ -37,9 +37,19 @@ export function shouldShowHover(
 	if (hoverEnabled === 'off') {
 		return false;
 	}
+	return isTriggerModifierPressed(multiCursorModifier, mouseEvent.event);
+}
+
+/**
+ * Returns true if the trigger modifier (inverse of multi-cursor modifier) is pressed.
+ * This works with both mouse and keyboard events by relying only on the modifier flags.
+ */
+export function isTriggerModifierPressed(
+	multiCursorModifier: 'altKey' | 'ctrlKey' | 'metaKey',
+	event: { ctrlKey: boolean; metaKey: boolean; altKey: boolean }
+): boolean {
 	if (multiCursorModifier === 'altKey') {
-		return mouseEvent.event.ctrlKey || mouseEvent.event.metaKey;
-	} else {
-		return mouseEvent.event.altKey;
+		return event.ctrlKey || event.metaKey;
 	}
+	return event.altKey; // multiCursorModifier is ctrlKey or metaKey
 }