src/vs/workbench/contrib/comments/browser/commentsEditorContribution.ts/CommentController/onEditorMouseUp
class CommentController:	private onEditorMouseUp(e: IEditorMouseEvent): void {
		if (!this.mouseDownInfo) {
			return;
		}

		const { lineNumber } = this.mouseDownInfo;
		this.mouseDownInfo = null;

		const range = e.target.range;

		if (!range || range.startLineNumber !== lineNumber) {
			return;
		}

		if (e.target.type !== MouseTargetType.GUTTER_LINE_DECORATIONS) {
			return;
		}

		if (!e.target.element) {
			return;
		}

		if (e.target.element.className.indexOf('comment-diff-added') >= 0) {
			const lineNumber = e.target.position!.lineNumber;
			this.addOrToggleCommentAtLine(lineNumber, e);
		}
	}