fix watermark

packages/dockview-demo/src/layout-grid/layoutGrid.tsx

@@ -25,6 +25,14 @@ import { selectedPanelAtom } from './footer';
 import { ExampleFunctions } from './panels/exampleFunctions';
 import { CompositeDisposable } from '../lifecycle';
 
+const WatermarkComponent = () => {
+    return (
+        <div style={{ backgroundColor: 'black', color: 'white' }}>
+            Watermark component
+        </div>
+    );
+};
+
 const Test = (props: IDockviewPanelProps) => {
     const [counter, setCounter] = React.useState<number>(0);
 
@@ -109,6 +117,7 @@ const components: PanelCollection<IDockviewPanelProps> = {
                 <DockviewReact
                     onReady={onReady}
                     components={components}
+                    watermarkComponent={WatermarkComponent}
                     tabHeight={20}
                     debug={true}
                 />
@@ -140,7 +149,9 @@ export const TestGrid = (props: IGridviewPanelProps) => {
     };
 
     const setSelectedPanel = useRecoilCallback(
-        ({ set }) => (value: string) => set(selectedPanelAtom, value),
+        ({ set }) =>
+            (value: string) =>
+                set(selectedPanelAtom, value),
         []
     );
 
@@ -192,11 +203,12 @@ export const TestGrid = (props: IGridviewPanelProps) => {
         };
     }, [api]);
 
-    const [coord, setCoord] = React.useState<{
+    const [coord, setCoord] =
-        x: number;
+        React.useState<{
-        y: number;
+            x: number;
-        panel: IGroupPanel;
+            y: number;
-    }>(undefined);
+            panel: IGroupPanel;
+        }>(undefined);
 
     const onTabContextMenu = React.useMemo(
         () => (event: TabContextMenuEvent) => {
@@ -276,7 +288,6 @@ export const TestGrid = (props: IGridviewPanelProps) => {
 const Watermark = (props: IWatermarkPanelProps) => {
     const [groups, setGroups] = React.useState<number>(props.containerApi.size);
     React.useEffect(() => {
-        console.log('mount');
         const disposable = new CompositeDisposable(
             props.containerApi.onDidLayoutChange(() => {
                 console.log(`groups2 ${props.containerApi.size}`);
@@ -285,7 +296,6 @@ const Watermark = (props: IWatermarkPanelProps) => {
         );
 
         return () => {
-            console.log('unmount');
             disposable.dispose();
         };
     }, []);
@@ -332,30 +342,7 @@ const Watermark = (props: IWatermarkPanelProps) => {
                     justifyContent: 'center',
                 }}
             >
-                {/* <svg
+                <span>Watermark component</span>
-                    width="300"
-                    height="300"
-                    viewBox="0 0 300 300"
-                    fill="none"
-                    xmlns="http://www.w3.org/2000/svg"
-                >
-                    <rect
-                        x="12.5"
-                        y="12.5"
-                        width="175"
-                        height="275"
-                        stroke="black"
-                        stroke-width="25"
-                    />
-                    <rect
-                        x="112.5"
-                        y="62.5"
-                        width="175"
-                        height="175"
-                        stroke="black"
-                        stroke-width="25"
-                    />
-                </svg> */}
             </div>
         </div>
     );

packages/dockview/src/__tests__/dockview/dockviewComponent.spec.ts

@@ -465,7 +465,7 @@ describe('dockviewComponent', () => {
 
         await panel2.api.close();
 
-        expect(dockview.size).toBe(0);
+        expect(dockview.size).toBe(1); // watermark
         expect(dockview.totalPanels).toBe(0);
     });
 
@@ -1178,6 +1178,89 @@ describe('dockviewComponent', () => {
         expect(panel1Spy).toBeCalledTimes(1);
     });
 
+    test('can add panel of same id if already removed', () => {
+        const container = document.createElement('div');
+
+        const dockview = new DockviewComponent(container, {
+            components: { default: PanelContentPartTest },
+        });
+
+        dockview.layout(500, 1000);
+
+        const panel1 = dockview.addPanel({
+            id: 'panel1',
+            component: 'default',
+            tabComponent: 'default',
+        });
+
+        expect(dockview.totalPanels).toBe(1);
+
+        panel1.api.close();
+
+        expect(dockview.totalPanels).toBe(0);
+
+        const panel1Again = dockview.addPanel({
+            id: 'panel1',
+            component: 'default',
+            tabComponent: 'default',
+        });
+
+        expect(dockview.totalPanels).toBe(1);
+
+        panel1Again.api.close();
+
+        expect(dockview.totalPanels).toBe(0);
+    });
+
+    test('last group is retained for watermark', () => {
+        const container = document.createElement('div');
+
+        const dockview = new DockviewComponent(container, {
+            components: { default: PanelContentPartTest },
+        });
+
+        dockview.layout(500, 1000);
+
+        const panel1 = dockview.addPanel({
+            id: 'panel1',
+            component: 'default',
+            tabComponent: 'default',
+        });
+
+        expect(dockview.size).toBe(1);
+        expect(dockview.totalPanels).toBe(1);
+
+        const group = panel1.group;
+
+        dockview.removePanel(panel1);
+
+        expect(group.model.hasWatermark).toBeTruthy();
+        expect(dockview.size).toBe(1);
+        expect(dockview.totalPanels).toBe(0);
+
+        const panel2 = dockview.addPanel({
+            id: 'panel2',
+            component: 'default',
+            tabComponent: 'default',
+        });
+
+        expect(group.model.hasWatermark).toBeFalsy();
+
+        const panel3 = dockview.addPanel({
+            id: 'panel3',
+            component: 'default',
+            tabComponent: 'default',
+        });
+
+        expect(dockview.size).toBe(1);
+        expect(dockview.totalPanels).toBe(2);
+
+        panel2.api.close();
+        expect(group.model.hasWatermark).toBeFalsy();
+        panel3.api.close();
+        expect(group.model.hasWatermark).toBeTruthy();
+    });
+
     test('panel is disposed of when removed', () => {
         const container = document.createElement('div');
 

packages/dockview/src/dockview/dockviewComponent.ts

@@ -470,7 +470,13 @@ export class DockviewComponent
 
         panel.dispose();
 
-        if (group.model.size === 0 && options.removeEmptyGroup) {
+        const retainGroupForWatermark = this.size === 1;
+
+        if (
+            !retainGroupForWatermark &&
+            group.model.size === 0 &&
+            options.removeEmptyGroup
+        ) {
             this.removeGroup(group);
         }
     }

packages/dockview/src/groupview/groupview.ts

@@ -150,38 +150,44 @@ export class Groupview extends CompositeDisposable implements IGroupview {
         this.layout(this._width, this._height);
     }
 
-    get isActive() {
+    get isActive(): boolean {
         return this._isGroupActive;
     }
 
-    get panels() {
+    get panels(): IGroupPanel[] {
         return this._panels;
     }
 
-    get size() {
+    get size(): number {
         return this._panels.length;
     }
 
-    get isEmpty() {
+    get isEmpty(): boolean {
         return this._panels.length === 0;
     }
 
-    get minimumHeight() {
+    get minimumHeight(): number {
         return 100;
     }
 
-    get maximumHeight() {
+    get maximumHeight(): number {
         return Number.MAX_SAFE_INTEGER;
     }
 
-    get minimumWidth() {
+    get minimumWidth(): number {
         return 100;
     }
 
-    get maximumWidth() {
+    get maximumWidth(): number {
         return Number.MAX_SAFE_INTEGER;
     }
 
+    get hasWatermark(): boolean {
+        return !!(
+            this.watermark && this.container.contains(this.watermark.element)
+        );
+    }
+
     constructor(
         private readonly container: HTMLElement,
         private accessor: IDockviewComponent,