How to move left panel to right and remove right one?

[Orangewithsugar]

I'm trying to do like this:

import {ApplicationShell} from '@theia/core/lib/browser/shell/application-shell';

export class CustomShell extends ApplicationShell {

    protected override initializeShell(): void {
        super.initializeShell();

        if (this.rightPanelHandler) {
            this.rightPanelHandler.dockPanel.dispose();
        }

        if (this.leftPanelHandler) {
            this.leftPanelHandler.dockPanel.dispose();
            this.leftPanelHandler = this.sidePanelHandlerFactory();
            this.leftPanelHandler.create('left', this.options.leftPanel);
            this.leftPanelHandler.dockPanel.widgetAdded.connect((_, widget) => this.fireDidAddWidget(widget));
            this.leftPanelHandler.dockPanel.widgetRemoved.connect((_, widget) => this.fireDidRemoveWidget(widget));

        }
    }
}

but it failed with:

logger-protocol.ts:113 2025-03-06T07:34:24.056Z root ERROR TypeError: Cannot read properties of null (reading 'addWidget')
    at __webpack_modules__.../node_modules/@phosphor/widgets/lib/dockpanel.js.DockPanel.addWidget (http://localhost:3000/bundle.js:16771:25)
    at TheiaDockPanel.addWidget (http://localhost:3000/bundle.js:47326:15)
    at SidePanelHandler.addWidget (http://localhost:3000/bundle.js:44732:24)
    at MogineShell.addWidget (http://localhost:3000/bundle.js:42760:40)
    at OutlineViewContribution.openView (http://localhost:3000/bundle.js:47517:25)
    at async OutlineViewContribution.initializeLayout (http://localhost:3000/vendors-node_modules_theia_core_shared_react_index_js-node_modules_theia_core_shared_vscode-l-403094.js:357:9)
    at async FrontendStopwatch.startAsync (http://localhost:3000/bundle.js:63521:24)
    at async FrontendApplication.createDefaultLayout (http://localhost:3000/bundle.js:33525:17)
    at async FrontendApplication.initializeLayout (http://localhost:3000/bundle.js:33496:13)

Best

[sdirix]

The right and left panel handlers are used throughout the application-shell so I don't think you can just dispose their dockPanels, as the application-shell does not expect nor handle this case. This is why you get the error message.

One way of "moving the left panel to the right" and "removing the right" could be to:

• Overwrite the way widgets are added, i.e. widgets which were indicated to open to the left, are added to the right instead, see here
• Overwrite the default options of the left panel to be of size 0 when it's empty. Then it can no longer be targeted via drag/drop etc. See here and here.

This way the left panel is essentially gone and every new workspace will open all views to the right. However if you open an old workspace, in which panels were still allowed to be left, then they will still show up on the left, as the layout restore does not go through this code. If you need to handle old workspaces like this, then you need to override the layout restore mechanism.

[Orangewithsugar]

Tyvm!!
I will try the methods that you provide , and i found why my menu is gone, it's because my window setting.

Best reguards.