diff --git a/packages/splitview/src/api/panePanelApi.ts b/packages/splitview/src/api/panePanelApi.ts
new file mode 100644
index 000000000..bb67c39e5
--- /dev/null
+++ b/packages/splitview/src/api/panePanelApi.ts
@@ -0,0 +1,22 @@
+import { Emitter, Event } from '../events';
+import { IPanelApi, PanelApi } from './panelApi';
+
+interface ExpansionEvent {
+    isExpanded: boolean;
+}
+
+export interface IPanePanelApi extends IPanelApi {
+    onDidExpansionChange: Event<ExpansionEvent>;
+}
+
+export class PanePanelApi extends PanelApi implements IPanePanelApi {
+    readonly _onDidExpansionChange = new Emitter<ExpansionEvent>({
+        emitLastValue: true,
+    });
+    readonly onDidExpansionChange: Event<ExpansionEvent> = this
+        ._onDidExpansionChange.event;
+
+    constructor() {
+        super();
+    }
+}
diff --git a/packages/splitview/src/paneview/componentPaneView.ts b/packages/splitview/src/paneview/componentPaneView.ts
index 3d12b8ca9..9726528e4 100644
--- a/packages/splitview/src/paneview/componentPaneView.ts
+++ b/packages/splitview/src/paneview/componentPaneView.ts
@@ -76,6 +76,17 @@ export class ComponentPaneView implements IComponentPaneView {
         this.paneview.layout(size, orthogonalSize);
     }
 
+    /**
+     * Resize the layout to fit the parent container
+     */
+    public resizeToFit(): void {
+        const {
+            width,
+            height,
+        } = this.element.parentElement.getBoundingClientRect();
+        this.layout(width, height);
+    }
+
     public dispose() {
         this.paneview.dispose();
     }
diff --git a/packages/splitview/src/paneview/paneview.ts b/packages/splitview/src/paneview/paneview.ts
index 49ae38efb..e946f8def 100644
--- a/packages/splitview/src/paneview/paneview.ts
+++ b/packages/splitview/src/paneview/paneview.ts
@@ -1,5 +1,5 @@
 import { SplitView, IView, Orientation } from '../splitview/splitview';
-import { IDisposable } from '../lifecycle';
+import { CompositeDisposable, IDisposable } from '../lifecycle';
 import { Emitter, Event } from '../events';
 import { addClasses, removeClasses } from '../dom';
 
@@ -13,7 +13,7 @@ export interface IPaneview extends IView {
     onDidChangeExpansionState: Event<boolean>;
 }
 
-export abstract class Pane implements IPaneview {
+export abstract class Pane extends CompositeDisposable implements IPaneview {
     private _element: HTMLElement;
     private _minimumBodySize: number;
     private _maximumBodySize: number;
@@ -81,6 +81,10 @@ export abstract class Pane implements IPaneview {
     }
 
     constructor(options: IPaneOptions) {
+        super();
+
+        this.addDisposables(this._onDidChange, this._onDidChangeExpansionState);
+
         this._element = document.createElement('div');
         this._element.className = 'pane';
 
diff --git a/packages/splitview/src/react/dockview/dockview.tsx b/packages/splitview/src/react/dockview/dockview.tsx
index 36842380d..c95528756 100644
--- a/packages/splitview/src/react/dockview/dockview.tsx
+++ b/packages/splitview/src/react/dockview/dockview.tsx
@@ -9,6 +9,7 @@ import {
     TabContextMenuEvent,
 } from '../../dockview/options';
 import { IGroupPanelApi } from '../../api/groupPanelApi';
+import { usePortalsLifecycle } from '../react';
 
 export interface IGroupPanelProps {
     api: IGroupPanelApi;
@@ -51,23 +52,12 @@ export interface IDockviewComponentProps {
 export const DockviewComponent: React.FunctionComponent<IDockviewComponentProps> = (
     props: IDockviewComponentProps
 ) => {
-    const domReference = React.useRef<HTMLDivElement>();
-    const layoutReference = React.useRef<ComponentDockview>();
+    const domRef = React.useRef<HTMLDivElement>();
+    const dockviewRef = React.useRef<ComponentDockview>();
 
-    const [portals, setPortals] = React.useState<React.ReactPortal[]>([]);
+    const [portals, addPortal] = usePortalsLifecycle();
 
     React.useEffect(() => {
-        const addPortal = (p: React.ReactPortal) => {
-            setPortals((portals) => [...portals, p]);
-            return {
-                dispose: () => {
-                    setPortals((portals) =>
-                        portals.filter((portal) => portal !== p)
-                    );
-                },
-            };
-        };
-
         const factory: GroupPanelFrameworkComponentFactory = {
             content: {
                 createComponent: (
@@ -95,7 +85,7 @@ export const DockviewComponent: React.FunctionComponent<IDockviewComponentProps>
 
         const element = document.createElement('div');
 
-        const layout = new ComponentDockview(element, {
+        const dockview = new ComponentDockview(element, {
             frameworkComponentFactory: factory,
             frameworkComponents: props.components,
             frameworkTabComponents: props.tabComponents,
@@ -105,28 +95,28 @@ export const DockviewComponent: React.FunctionComponent<IDockviewComponentProps>
             // orientation: props.orientation,
         });
 
-        layoutReference.current = layout;
-        domReference.current.appendChild(layoutReference.current.element);
-
-        layout.deserializer = new ReactPanelDeserialzier(layout);
-
-        layout.resizeToFit();
+        domRef.current.appendChild(dockview.element);
+        dockview.deserializer = new ReactPanelDeserialzier(dockview);
 
         if (props.serializedLayout) {
-            layout.deserialize(props.serializedLayout);
+            dockview.deserialize(props.serializedLayout);
         }
 
+        dockview.resizeToFit();
+
         if (props.onReady) {
-            props.onReady({ api: layout });
+            props.onReady({ api: dockview });
         }
 
+        dockviewRef.current = dockview;
+
         return () => {
-            layout.dispose();
+            dockview.dispose();
         };
     }, []);
 
     React.useEffect(() => {
-        const disposable = layoutReference.current.onTabContextMenu((event) => {
+        const disposable = dockviewRef.current.onTabContextMenu((event) => {
             props.onTabContextMenu(event);
         });
 
@@ -136,9 +126,7 @@ export const DockviewComponent: React.FunctionComponent<IDockviewComponentProps>
     }, [props.onTabContextMenu]);
 
     React.useEffect(() => {
-        layoutReference.current.setAutoResizeToFit(
-            props.autoSizeToFitContainer
-        );
+        dockviewRef.current.setAutoResizeToFit(props.autoSizeToFitContainer);
     }, [props.autoSizeToFitContainer]);
 
     return (
@@ -147,7 +135,7 @@ export const DockviewComponent: React.FunctionComponent<IDockviewComponentProps>
                 // height: '100%',
                 width: '100%',
             }}
-            ref={domReference}
+            ref={domRef}
         >
             {portals}
         </div>
diff --git a/packages/splitview/src/react/dockview/reactContentPart.ts b/packages/splitview/src/react/dockview/reactContentPart.ts
index fdf17eb60..107e6e8ae 100644
--- a/packages/splitview/src/react/dockview/reactContentPart.ts
+++ b/packages/splitview/src/react/dockview/reactContentPart.ts
@@ -54,9 +54,6 @@ export class ReactPanelContentPart implements PanelContentPart {
         return Promise.resolve(ClosePanelResult.CLOSE);
     }
 
-    public focus(): void {}
-    public onHide(): void {}
-
     public dispose() {
         this.part?.dispose();
     }
diff --git a/packages/splitview/src/react/dockview/reactHeaderPart.ts b/packages/splitview/src/react/dockview/reactHeaderPart.ts
index f5d89ff96..8d4b55b69 100644
--- a/packages/splitview/src/react/dockview/reactHeaderPart.ts
+++ b/packages/splitview/src/react/dockview/reactHeaderPart.ts
@@ -1,5 +1,4 @@
 import * as React from 'react';
-import { IGroupPanelApi } from '../../api/groupPanelApi';
 import {
     PanelHeaderPart,
     GroupPanelPartInitParameters,
diff --git a/packages/splitview/src/react/gridview/gridview.tsx b/packages/splitview/src/react/gridview/gridview.tsx
index c9c4d78d5..76f895554 100644
--- a/packages/splitview/src/react/gridview/gridview.tsx
+++ b/packages/splitview/src/react/gridview/gridview.tsx
@@ -6,6 +6,7 @@ import {
 import { IGridPanelApi } from '../../api/gridPanelApi';
 import { Orientation } from '../../splitview/splitview';
 import { ReactComponentGridView } from './reactComponentGridView';
+import { usePortalsLifecycle } from '../react';
 
 export interface GridviewReadyEvent {
     api: IComponentGridview;
@@ -26,23 +27,12 @@ export interface IGridviewComponentProps {
 export const GridviewComponent: React.FunctionComponent<IGridviewComponentProps> = (
     props: IGridviewComponentProps
 ) => {
-    const domReference = React.useRef<HTMLDivElement>();
-    const gridview = React.useRef<IComponentGridview>();
-    const [portals, setPortals] = React.useState<React.ReactPortal[]>([]);
-
-    const addPortal = React.useCallback((p: React.ReactPortal) => {
-        setPortals((portals) => [...portals, p]);
-        return {
-            dispose: () => {
-                setPortals((portals) =>
-                    portals.filter((portal) => portal !== p)
-                );
-            },
-        };
-    }, []);
+    const domRef = React.useRef<HTMLDivElement>();
+    const gridviewRef = React.useRef<IComponentGridview>();
+    const [portals, addPortal] = usePortalsLifecycle();
 
     React.useEffect(() => {
-        gridview.current = new ComponentGridview(domReference.current, {
+        const gridview = new ComponentGridview(domRef.current, {
             orientation: props.orientation,
             frameworkComponents: props.components,
             frameworkComponentFactory: {
@@ -59,9 +49,17 @@ export const GridviewComponent: React.FunctionComponent<IGridviewComponentProps>
             },
         });
 
+        // gridview.resizeToFit();
+
         if (props.onReady) {
-            props.onReady({ api: gridview.current });
+            props.onReady({ api: gridview });
         }
+
+        gridviewRef.current = gridview;
+
+        return () => {
+            gridview.dispose();
+        };
     }, []);
 
     return (
@@ -70,7 +68,7 @@ export const GridviewComponent: React.FunctionComponent<IGridviewComponentProps>
                 height: '100%',
                 width: '100%',
             }}
-            ref={domReference}
+            ref={domRef}
         >
             {portals}
         </div>
diff --git a/packages/splitview/src/react/paneview/paneview.tsx b/packages/splitview/src/react/paneview/paneview.tsx
index b8ee736fe..2728e6e06 100644
--- a/packages/splitview/src/react/paneview/paneview.tsx
+++ b/packages/splitview/src/react/paneview/paneview.tsx
@@ -1,17 +1,18 @@
 import * as React from 'react';
-import { IPanelApi } from '../../api/panelApi';
+import { IPanePanelApi } from '../../api/panePanelApi';
 import {
     ComponentPaneView,
     IComponentPaneView,
 } from '../../paneview/componentPaneView';
 import { PaneReact } from './reactPane';
+import { usePortalsLifecycle } from '../react';
 
 export interface PaneviewReadyEvent {
     api: IComponentPaneView;
 }
 
 export interface IPaneviewPanelProps {
-    api: IPanelApi;
+    api: IPanePanelApi;
 }
 
 export interface IPaneviewComponentProps {
@@ -24,23 +25,12 @@ export interface IPaneviewComponentProps {
 export const PaneViewComponent: React.FunctionComponent<IPaneviewComponentProps> = (
     props: IPaneviewComponentProps
 ) => {
-    const domReference = React.useRef<HTMLDivElement>();
-    const splitpanel = React.useRef<IComponentPaneView>();
-    const [portals, setPortals] = React.useState<React.ReactPortal[]>([]);
-
-    const addPortal = React.useCallback((p: React.ReactPortal) => {
-        setPortals((portals) => [...portals, p]);
-        return {
-            dispose: () => {
-                setPortals((portals) =>
-                    portals.filter((portal) => portal !== p)
-                );
-            },
-        };
-    }, []);
+    const domRef = React.useRef<HTMLDivElement>();
+    const paneviewRef = React.useRef<IComponentPaneView>();
+    const [portals, addPortal] = usePortalsLifecycle();
 
     React.useEffect(() => {
-        splitpanel.current = new ComponentPaneView(domReference.current, {
+        const paneview = new ComponentPaneView(domRef.current, {
             frameworkComponents: props.components,
             components: {},
             frameworkWrapper: {
@@ -56,16 +46,20 @@ export const PaneViewComponent: React.FunctionComponent<IPaneviewComponentProps>
             },
         });
 
-        const { width, height } = domReference.current.getBoundingClientRect();
+        const { width, height } = domRef.current.getBoundingClientRect();
         const [size, orthogonalSize] = [height, width];
-        splitpanel.current.layout(size, orthogonalSize);
+        paneview.layout(size, orthogonalSize);
 
         if (props.onReady) {
-            props.onReady({ api: splitpanel.current });
+            props.onReady({ api: paneview });
         }
 
+        paneview.resizeToFit();
+
+        paneviewRef.current = paneview;
+
         return () => {
-            splitpanel.current.dispose();
+            paneview.dispose();
         };
     }, []);
 
@@ -75,7 +69,7 @@ export const PaneViewComponent: React.FunctionComponent<IPaneviewComponentProps>
                 height: '100%',
                 width: '100%',
             }}
-            ref={domReference}
+            ref={domRef}
         >
             {portals}
         </div>
diff --git a/packages/splitview/src/react/paneview/reactPane.tsx b/packages/splitview/src/react/paneview/reactPane.tsx
index 160d1b386..f94389c9d 100644
--- a/packages/splitview/src/react/paneview/reactPane.tsx
+++ b/packages/splitview/src/react/paneview/reactPane.tsx
@@ -1,12 +1,12 @@
 import * as React from 'react';
-import { BaseViewApi, IBaseViewApi } from '../../api/api';
+import { IPanePanelApi, PanePanelApi } from '../../api/panePanelApi';
 import { Pane } from '../../paneview/paneview';
 import { ReactLayout } from '../dockview/dockview';
 import { ReactPart } from '../react';
 
 export class PaneReact extends Pane {
     private params: {};
-    private api: IBaseViewApi;
+    private api: PanePanelApi;
 
     private contentPart: ReactPart;
     private headerPart: ReactPart;
@@ -27,7 +27,14 @@ export class PaneReact extends Pane {
             // options.isExpanded
         });
 
-        this.api = new BaseViewApi();
+        this.api = new PanePanelApi();
+
+        this.addDisposables(
+            this.onDidChangeExpansionState((isExpanded) => {
+                this.api._onDidExpansionChange.fire({ isExpanded });
+            })
+        );
+
         this.render();
     }
 
@@ -62,6 +69,7 @@ export class PaneReact extends Pane {
     }
 
     public dispose() {
+        super.dispose();
         this.headerPart.dispose();
         this.contentPart.dispose();
         this.api.dispose();
diff --git a/packages/splitview/src/react/react.tsx b/packages/splitview/src/react/react.tsx
index 2032d24fb..268cd46dd 100644
--- a/packages/splitview/src/react/react.tsx
+++ b/packages/splitview/src/react/react.tsx
@@ -118,3 +118,28 @@ export class ReactPart implements IDisposable {
         this.disposed = true;
     }
 }
+
+/**
+ * A React Hook that returns an array of portals to be rendered by the user of this hook
+ * and a disposable function to add a portal. Calling dispose remove this portal from the
+ * portal array
+ */
+export const usePortalsLifecycle = () => {
+    const [portals, setPortals] = React.useState<React.ReactPortal[]>([]);
+
+    const addPortal = React.useCallback((p: React.ReactPortal) => {
+        setPortals((portals) => [...portals, p]);
+        return {
+            dispose: () => {
+                setPortals((portals) =>
+                    portals.filter((portal) => portal !== p)
+                );
+            },
+        };
+    }, []);
+
+    return [portals, addPortal] as [
+        React.ReactPortal[],
+        (portal: React.ReactPortal) => IDisposable
+    ];
+};
diff --git a/packages/splitview/src/react/splitview/splitview.tsx b/packages/splitview/src/react/splitview/splitview.tsx
index 6f0e69f29..099c29263 100644
--- a/packages/splitview/src/react/splitview/splitview.tsx
+++ b/packages/splitview/src/react/splitview/splitview.tsx
@@ -5,6 +5,7 @@ import {
     ComponentSplitview,
 } from '../../splitview/componentSplitview';
 import { Orientation } from '../../splitview/splitview';
+import { usePortalsLifecycle } from '../react';
 import { ReactComponentView } from './reactComponentView';
 
 export interface SplitviewReadyEvent {
@@ -26,23 +27,12 @@ export interface ISplitviewComponentProps {
 export const SplitviewComponent: React.FunctionComponent<ISplitviewComponentProps> = (
     props: ISplitviewComponentProps
 ) => {
-    const domReference = React.useRef<HTMLDivElement>();
-    const splitpanel = React.useRef<IComponentSplitview>();
-    const [portals, setPortals] = React.useState<React.ReactPortal[]>([]);
-
-    const addPortal = React.useCallback((p: React.ReactPortal) => {
-        setPortals((portals) => [...portals, p]);
-        return {
-            dispose: () => {
-                setPortals((portals) =>
-                    portals.filter((portal) => portal !== p)
-                );
-            },
-        };
-    }, []);
+    const domRef = React.useRef<HTMLDivElement>();
+    const splitviewRef = React.useRef<IComponentSplitview>();
+    const [portals, addPortal] = usePortalsLifecycle();
 
     React.useEffect(() => {
-        splitpanel.current = new ComponentSplitview(domReference.current, {
+        const splitview = new ComponentSplitview(domRef.current, {
             orientation: props.orientation,
             frameworkComponents: props.components,
             frameworkWrapper: {
@@ -55,19 +45,16 @@ export const SplitviewComponent: React.FunctionComponent<ISplitviewComponentProp
             proportionalLayout: false,
         });
 
-        const { width, height } = domReference.current.getBoundingClientRect();
-        const [size, orthogonalSize] =
-            props.orientation === Orientation.HORIZONTAL
-                ? [width, height]
-                : [height, width];
-        splitpanel.current.layout(size, orthogonalSize);
+        splitview.resizeToFit();
 
         if (props.onReady) {
-            props.onReady({ api: splitpanel.current });
+            props.onReady({ api: splitview });
         }
 
+        splitviewRef.current = splitview;
+
         return () => {
-            splitpanel.current.dispose();
+            splitview.dispose();
         };
     }, []);
 
@@ -77,7 +64,7 @@ export const SplitviewComponent: React.FunctionComponent<ISplitviewComponentProp
                 height: '100%',
                 width: '100%',
             }}
-            ref={domReference}
+            ref={domRef}
         >
             {portals}
         </div>
diff --git a/packages/splitview/src/splitview/componentSplitview.ts b/packages/splitview/src/splitview/componentSplitview.ts
index 4fddb962f..b8422cfcd 100644
--- a/packages/splitview/src/splitview/componentSplitview.ts
+++ b/packages/splitview/src/splitview/componentSplitview.ts
@@ -79,6 +79,17 @@ export class ComponentSplitview implements IComponentSplitview {
         };
     }
 
+    /**
+     * Resize the layout to fit the parent container
+     */
+    public resizeToFit(): void {
+        const {
+            width,
+            height,
+        } = this.element.parentElement.getBoundingClientRect();
+        this.layout(width, height);
+    }
+
     private registerView(view: ISerializableView) {
         //
     }
diff --git a/vscode.code-workspace b/vscode.code-workspace
index d6c7df5fe..dfc97e8cf 100644
--- a/vscode.code-workspace
+++ b/vscode.code-workspace
@@ -4,5 +4,7 @@
 		"path": "."
 	}
 ],
-  "settings": {}
+"settings": {
+	"editor.formatOnSave": true
+}
 }