Fix #52901

src/vs/workbench/api/electron-browser/mainThreadTreeViews.ts

@@ -34,6 +34,7 @@ export class MainThreadTreeViews extends Disposable implements MainThreadTreeVie
 		if (viewer) {
 			viewer.dataProvider = dataProvider;
 			this.registerListeners(treeViewId, viewer);
+			this._proxy.$setVisible(treeViewId, viewer.visible);
 		} else {
 			this.notificationService.error('No view is registered with id: ' + treeViewId);
 		}

src/vs/workbench/api/node/extHostTreeViews.ts

@@ -125,7 +125,7 @@ class ExtHostTreeView<T> extends Disposable {
 	private elements: Map<TreeItemHandle, T> = new Map<TreeItemHandle, T>();
 	private nodes: Map<T, TreeNode> = new Map<T, TreeNode>();
 
-	private _visible: boolean = true;
+	private _visible: boolean = false;
 	get visible(): boolean { return this._visible; }
 
 	private _selectedHandles: TreeItemHandle[] = [];

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

@@ -242,7 +242,12 @@ export class CustomTreeViewer extends Disposable implements ITreeViewer {
 		return this._hasIconForLeafNode;
 	}
 
+	get visible(): boolean {
+		return this.isVisible;
+	}
+
 	setVisibility(isVisible: boolean): void {
+		isVisible = !!isVisible;
 		if (this.isVisible === isVisible) {
 			return;
 		}

src/vs/workbench/common/views.ts

@@ -229,6 +229,8 @@ export interface ITreeViewer extends IDisposable {
 
 	readonly onDidChangeVisibility: Event<boolean>;
 
+	readonly visible: boolean;
+
 	refresh(treeItems?: ITreeItem[]): TPromise<void>;
 
 	setVisibility(visible: boolean): void;