Fixes #108160: Handle padding in mouse target computation

src/vs/editor/browser/controller/mouseTarget.ts

@@ -329,6 +329,14 @@ export class HitTestContext {
 		return this._context.viewLayout.isAfterLines(mouseVerticalOffset);
 	}
 
+	public isInTopPadding(mouseVerticalOffset: number): boolean {
+		return this._context.viewLayout.isInTopPadding(mouseVerticalOffset);
+	}
+
+	public isInBottomPadding(mouseVerticalOffset: number): boolean {
+		return this._context.viewLayout.isInBottomPadding(mouseVerticalOffset);
+	}
+
 	public getVerticalOffsetForLineNumber(lineNumber: number): number {
 		return this._context.viewLayout.getVerticalOffsetForLineNumber(lineNumber);
 	}
@@ -656,8 +664,12 @@ export class MouseTargetFactory {
 			return null;
 		}
 
+		if (ctx.isInTopPadding(request.mouseVerticalOffset)) {
+			return request.fulfill(MouseTargetType.CONTENT_EMPTY, new Position(1, 1), undefined, EMPTY_CONTENT_AFTER_LINES);
+		}
+
 		// Check if it is below any lines and any view zones
-		if (ctx.isAfterLines(request.mouseVerticalOffset)) {
+		if (ctx.isAfterLines(request.mouseVerticalOffset) || ctx.isInBottomPadding(request.mouseVerticalOffset)) {
 			// This most likely indicates it happened after the last view-line
 			const lineCount = ctx.model.getLineCount();
 			const maxLineColumn = ctx.model.getLineMaxColumn(lineCount);

src/vs/editor/common/viewLayout/linesLayout.ts

@@ -546,6 +546,23 @@ export class LinesLayout {
 		return verticalOffset > totalHeight;
 	}
 
+	public isInTopPadding(verticalOffset: number): boolean {
+		if (this._paddingTop === 0) {
+			return false;
+		}
+		this._checkPendingChanges();
+		return (verticalOffset < this._paddingTop);
+	}
+
+	public isInBottomPadding(verticalOffset: number): boolean {
+		if (this._paddingBottom === 0) {
+			return false;
+		}
+		this._checkPendingChanges();
+		const totalHeight = this.getLinesTotalHeight();
+		return (verticalOffset >= totalHeight - this._paddingBottom);
+	}
+
 	/**
 	 * Find the first line number that is at or after vertical offset `verticalOffset`.
 	 * i.e. if getVerticalOffsetForLine(line) is x and getVerticalOffsetForLine(line + 1) is y, then

src/vs/editor/common/viewLayout/viewLayout.ts

@@ -364,6 +364,13 @@ export class ViewLayout extends Disposable implements IViewLayout {
 	public isAfterLines(verticalOffset: number): boolean {
 		return this._linesLayout.isAfterLines(verticalOffset);
 	}
+	public isInTopPadding(verticalOffset: number): boolean {
+		return this._linesLayout.isInTopPadding(verticalOffset);
+	}
+	isInBottomPadding(verticalOffset: number): boolean {
+		return this._linesLayout.isInBottomPadding(verticalOffset);
+	}
+
 	public getLineNumberAtVerticalOffset(verticalOffset: number): number {
 		return this._linesLayout.getLineNumberAtOrAfterVerticalOffset(verticalOffset);
 	}

src/vs/editor/common/viewModel/viewModel.ts

@@ -61,6 +61,8 @@ export interface IViewLayout {
 	getWhitespaces(): IEditorWhitespace[];
 
 	isAfterLines(verticalOffset: number): boolean;
+	isInTopPadding(verticalOffset: number): boolean;
+	isInBottomPadding(verticalOffset: number): boolean;
 	getLineNumberAtVerticalOffset(verticalOffset: number): number;
 	getVerticalOffsetForLineNumber(lineNumber: number): number;
 	getWhitespaceAtVerticalOffset(verticalOffset: number): IViewWhitespaceViewportData | null;