fixes #33383

src/vs/workbench/parts/scm/electron-browser/scmViewlet.ts

@@ -570,6 +570,10 @@ export class SCMViewlet extends PersistentViewsViewlet {
 		return this.instantiationService.createInstance(viewDescriptor.ctor, initialSize, options);
 	}
 
+	protected getDefaultViewSize(): number | undefined {
+		return this.dimension && this.dimension.height / this.views.length;
+	}
+
 	getOptimalWidth(): number {
 		return 400;
 	}

src/vs/workbench/parts/views/browser/views.ts

@@ -324,7 +324,7 @@ export class ViewsViewlet extends Viewlet {
 
 	private splitView: SplitView;
 	private viewHeaderContextMenuListeners: IDisposable[] = [];
-	private dimension: Dimension;
+	protected dimension: Dimension;
 	private viewletSettings: object;
 
 	private readonly viewsContextKeys: Set<string> = new Set<string>();
@@ -553,7 +553,7 @@ export class ViewsViewlet extends Viewlet {
 					let viewState = this.viewsStates.get(viewDescriptor.id);
 					let index = visible.indexOf(viewDescriptor);
 					const view = this.createView(viewDescriptor,
-						viewState ? viewState.size : void 0,
+						viewState ? viewState.size : this.getDefaultViewSize(),
 						{
 							id: viewDescriptor.id,
 							name: viewDescriptor.name,
@@ -575,6 +575,10 @@ export class ViewsViewlet extends Viewlet {
 		return TPromise.as([]);
 	}
 
+	protected getDefaultViewSize(): number | undefined {
+		return undefined;
+	}
+
 	private attachViewStyler(widget: IThemable, options?: { noContrastBorder?: boolean }): IDisposable {
 		return attachStyler(this.themeService, {
 			headerForeground: SIDE_BAR_SECTION_HEADER_FOREGROUND,