Remove resizer from fullscreen modules(like multiroom) (#33684)

* Fix multiroom with new resizer

* Fix multiroom with new resizer

* Add jest test

* Add if/else and comments

apps/web/src/components/structures/LoggedInView.tsx

@@ -795,8 +795,12 @@ class LoggedInView extends React.Component<IProps, IState> {
         );
 
         const roomView = <div className="mx_RoomView_wrapper">{pageElement}</div>;
-        const content =
-            useNewRoomList && this.resizerViewModel ? (
+
+        let content: React.ReactNode;
+        if (useNewRoomList && this.resizerViewModel && !moduleRenderer) {
+            // New room list owned by element-web: resizable layout with a draggable separator.
+            // The SpacePanel lives inside GroupView (leftPanel omits it when the new room list is enabled).
+            content = (
                 <GroupView vm={this.resizerViewModel}>
                     <SpacePanel />
                     <LeftResizablePanelView
@@ -811,13 +815,21 @@ class LoggedInView extends React.Component<IProps, IState> {
                     <SeparatorView className="mx_Separator" vm={this.resizerViewModel} />
                     <Panel className="mx_LeftPanel_panel">{roomView}</Panel>
                 </GroupView>
-            ) : (
+            );
+        } else {
+            // Fallback layout: the old room list, or a module's full-screen view (e.g. multiroom) which
+            // must not use the resizable layout above. SpacePanel is guarded on useNewRoomList to avoid a
+            // duplicate (the old room list already renders one inside leftPanel); the legacy ResizeHandle is
+            // dropped for module views, which manage their own layout.
+            content = (
                 <>
+                    {useNewRoomList && <SpacePanel />}
                     {leftPanel}
                     {!moduleRenderer && <ResizeHandle passRef={this.resizeHandler} id="lp-resizer" />}
                     {roomView}
                 </>
             );
+        }
 
         return (
             <MatrixClientContextProvider client={this._matrixClient}>

apps/web/test/unit-tests/components/structures/LoggedInView-test.tsx

@@ -39,6 +39,7 @@ import { Action } from "../../../../src/dispatcher/actions";
 import Modal from "../../../../src/Modal";
 import { SETTINGS } from "../../../../src/settings/Settings";
 import ToastStore from "../../../../src/stores/ToastStore";
+import { ModuleApi } from "../../../../src/modules/Api";
 
 // Create a mock resizer instance that can be shared across tests
 const mockResizerInstance = {
@@ -614,6 +615,42 @@ describe("<LoggedInView />", () => {
         });
     });
 
+    describe("module-rendered fullscreen view (e.g. multiroom)", () => {
+        // A page_type for which a module registers a custom full-screen renderer.
+        const modulePageType = "io.element.test_fullscreen";
+
+        beforeEach(async () => {
+            await SettingsStore.setValue("feature_new_room_list", null, SettingLevel.DEVICE, true);
+            ModuleApi.instance.navigation.registerLocationRenderer(modulePageType, () => (
+                <div data-testid="module-content" />
+            ));
+        });
+
+        afterEach(async () => {
+            ModuleApi.instance.navigation.locationRenderers.delete(modulePageType);
+            await SettingsStore.setValue("feature_new_room_list", null, SettingLevel.DEVICE, false);
+        });
+
+        it("renders the resizable separator for a normal room view with the new room list", () => {
+            const { container } = getComponent({ page_type: "room" });
+
+            // With the new room list and no module renderer, the resizable left panel and its separator are used.
+            expect(container.querySelector(".mx_Separator")).toBeInTheDocument();
+        });
+
+        it("does not render the resizer for a module-rendered fullscreen view, but keeps the space panel", () => {
+            const { container, getByTestId } = getComponent({ page_type: modulePageType });
+
+            // The module's full-screen content is shown...
+            expect(getByTestId("module-content")).toBeInTheDocument();
+            // ...without the resizable separator or the legacy resize handle...
+            expect(container.querySelector(".mx_Separator")).not.toBeInTheDocument();
+            expect(container.querySelector(".mx_ResizeHandle")).not.toBeInTheDocument();
+            // ...while the space panel rail remains visible.
+            expect(container.querySelector(".mx_SpacePanel")).toBeInTheDocument();
+        });
+    });
+
     describe("create a new resizer when page_type changes", () => {
         afterEach(() => {
             jest.clearAllMocks();