breadcrumbs - prevent scrollbar flashing

src/vs/base/browser/ui/breadcrumbs/breadcrumbsWidget.ts

@@ -114,13 +114,13 @@ export class BreadcrumbsWidget {
 	}
 
 	layout(dim: dom.Dimension): void {
-		if (!dim) {
-			this._scrollable.scanDomNode();
-		} else {
+		if (dim) {
 			this._domNode.style.width = `${dim.width}px`;
 			this._domNode.style.height = `${dim.height}px`;
-			this._scrollable.scanDomNode();
 		}
+		this._scrollable.setRevealOnScroll(false);
+		this._scrollable.scanDomNode();
+		this._scrollable.setRevealOnScroll(true);
 	}
 
 	style(style: IBreadcrumbsWidgetStyles): void {
@@ -206,7 +206,9 @@ export class BreadcrumbsWidget {
 	private _reveal(nth: number): void {
 		const node = this._nodes[nth];
 		if (node) {
+			this._scrollable.setRevealOnScroll(false);
 			this._scrollable.setScrollPosition({ scrollLeft: node.offsetLeft });
+			this._scrollable.setRevealOnScroll(true);
 		}
 	}
 

src/vs/base/browser/ui/scrollbar/scrollableElement.ts

@@ -163,6 +163,8 @@ export abstract class AbstractScrollableElement extends Widget {
 	private readonly _hideTimeout: TimeoutTimer;
 	private _shouldRender: boolean;
 
+	private _revealOnScroll: boolean;
+
 	private readonly _onScroll = this._register(new Emitter<ScrollEvent>());
 	public readonly onScroll: Event<ScrollEvent> = this._onScroll.event;
 
@@ -221,6 +223,8 @@ export abstract class AbstractScrollableElement extends Widget {
 		this._mouseIsOver = false;
 
 		this._shouldRender = true;
+
+		this._revealOnScroll = true;
 	}
 
 	public dispose(): void {
@@ -286,6 +290,10 @@ export abstract class AbstractScrollableElement extends Widget {
 		}
 	}
 
+	public setRevealOnScroll(value: boolean) {
+		this._revealOnScroll = value;
+	}
+
 	// -------------------- mouse wheel scrolling --------------------
 
 	private _setListeningToMouseWheel(shouldListen: boolean): void {
@@ -382,7 +390,9 @@ export abstract class AbstractScrollableElement extends Widget {
 			this._shouldRender = true;
 		}
 
-		this._reveal();
+		if (this._revealOnScroll) {
+			this._reveal();
+		}
 
 		if (!this._options.lazyRender) {
 			this._render();