fixes #46180

src/vs/base/parts/tree/browser/treeImpl.ts

@@ -122,8 +122,8 @@ export class Tree implements _.ITree {
 		return this.view.getHTMLElement();
 	}
 
-	public layout(height?: number): void {
-		this.view.layout(height);
+	public layout(height?: number, width?: number): void {
+		this.view.layout(height, width);
 	}
 
 	public domFocus(): void {

src/vs/base/parts/tree/browser/treeView.ts

@@ -636,7 +636,7 @@ export class TreeView extends HeightMap {
 		return this.onHiddenScrollTop === null;
 	}
 
-	public layout(height?: number): void {
+	public layout(height?: number, width?: number): void {
 		if (!this.isTreeVisible()) {
 			return;
 		}
@@ -645,7 +645,7 @@ export class TreeView extends HeightMap {
 		this.scrollHeight = this.getContentHeight();
 
 		if (this.horizontalScrolling) {
-			this.viewWidth = DOM.getContentWidth(this.wrapper);
+			this.viewWidth = width || DOM.getContentWidth(this.wrapper);
 		}
 	}
 

src/vs/workbench/parts/markers/electron-browser/markersPanel.ts

@@ -91,7 +91,7 @@ export class MarkersPanel extends Panel {
 	}
 
 	public layout(dimension: builder.Dimension): void {
-		this.tree.layout(dimension.height);
+		this.tree.layout(dimension.height, dimension.width);
 	}
 
 	public focus(): void {