fix #59333

src/vs/workbench/browser/parts/editor/breadcrumbsControl.ts

@@ -365,7 +365,7 @@ export class BreadcrumbsControl {
 				let pickerArrowOffset: number;
 
 				let data = dom.getDomNodePagePosition(event.node.firstChild as HTMLElement);
-				let y = data.top + data.height - pickerArrowSize;
+				let y = data.top + data.height + pickerArrowSize;
 				if (y + maxHeight >= window.innerHeight) {
 					maxHeight = window.innerHeight - y - 30 /* room for shadow and status bar*/;
 				}

src/vs/workbench/browser/parts/editor/breadcrumbsPicker.ts

@@ -80,9 +80,7 @@ export abstract class BreadcrumbsPicker {
 		const color = theme.getColor(breadcrumbsPickerBackground);
 
 		this._arrow = document.createElement('div');
-		this._arrow.style.width = '0';
-		this._arrow.style.borderStyle = 'solid';
-		this._arrow.style.borderWidth = '8px';
+		this._arrow.className = 'arrow';
 		this._arrow.style.borderColor = `transparent transparent ${color.toString()}`;
 		this._domNode.appendChild(this._arrow);
 
@@ -186,6 +184,7 @@ export abstract class BreadcrumbsPicker {
 
 		this._domNode.style.height = `${totalHeight}px`;
 		this._domNode.style.width = `${info.width}px`;
+		this._arrow.style.top = `-${2 * info.arrowSize}px`;
 		this._arrow.style.borderWidth = `${info.arrowSize}px`;
 		this._arrow.style.marginLeft = `${info.arrowOffset}px`;
 		this._treeContainer.style.height = `${treeHeight}px`;

src/vs/workbench/browser/parts/editor/media/breadcrumbscontrol.css

@@ -19,6 +19,12 @@
 
 /* todo@joh move somewhere else */
 
+.monaco-workbench .monaco-breadcrumbs-picker .arrow {
+	position: absolute;
+	width: 0;
+	border-style: solid;
+}
+
 .monaco-workbench .monaco-breadcrumbs-picker .picker-item {
 	line-height: 22px;
 	flex: 1;