feat: explore perspective mechanisms by CamilleLetavernier · Pull Request #320 · eclipsesource/theia

CamilleLetavernier · 2026-07-07T09:05:39Z

What it does

Add a new Perspective Service with a Command to switch perspectives
Add two perspectives: Theia IDE (Default) and AI First
The default perspectives simply shows whichever views are configured to open when no layout data is available
The AI First perspective includes the AI Chat in the main area, and Explorer/SCM on the right (left side is reserved for future new views, e.g. AI Sessions)
Perspective can optionally hide chrome: ~~menu bars~~, status bar, collapse areas, ...
- Menu bar hiding was removed in the last iteration: slightly complex due to multiple implementations (Browser, Electron Native, Electron Custom, MacOS...), and we probably want to "filter" menus rather than remove them entirely anyway
When a Perspective defines a default area for a view, that is different from the view's default area, the Perspective "wins" (So a perspective can move an existing view to a different location).
By default, perspective are pretty open: they define a default layout with a set of views, but users are still free to reorder them however they like (move views around, close/open views, ...)

How to test

F1 > Switch Perspective...
Select AI First
The new layout should be applied
- At the moment, open views and editors are never closed; they are only rearranged (follow-up required)
- New views may be opened if they are not open already
F1 > Switch Perspective > AI First (Active)
- Nothing happens: this is already the active perspective
F1 > Switch Perspective > Theia IDE
- The default perspective is restored in its latest known state

Follow-ups

Perspective Contribution improvements: Perspective contribution point #284
Perspective Layout persistence: Per-perspective layout persistence #285
Handle Hide/Close views: views that are not part of the target perspective should be either closed or hidden/disabled
- This is a potentially complex issue as we don't want to lose "Transient state". Switching back and forth between perspective should restore the initial state as much as possible (so closing/reopening the view might not be a good solution)
Handle disabling areas: currently, perspectives can indicate that an area (left/right/bottom) should be collapsed by default, but they can't prevent users from re-opening them. This is probably related to the Hide/Close views, as this mechanism is only interesting for perspectives that want to really strictly control what should be shown to the user, and how it should be shown (locked-down mode).
Handle secondary windows: currently, secondary windows are kept outside of the perspective mechanism. They remain open where they are when switching perspectives. When closing Theia, they are attached back to their preferred location and then persisted in the Layout Data

Breaking changes

This PR introduces breaking changes and requires careful review. If yes, the breaking changes section in the changelog has been updated.

Attribution

Review checklist

As an author, I have thoroughly tested my changes and carefully followed the review guidelines
User-facing text is internationalized using the nls service (for details, please see the Internationalization/Localization section in the Coding Guidelines)

Reminder for reviewers

As a reviewer, I agree to behave in accordance with the review guidelines

sdirix · 2026-07-07T09:44:01Z

+    protected applyChrome(descriptor: PerspectiveDescriptor): void {
+        const perspectiveHidesMenu = descriptor.chromeOptions?.hideMenuBar ?? false;
+        const prefHidesMenu = ['compact', 'hidden'].includes(
+            this.corePreferences['window.menuBarVisibility']
+        );
+        this.shell.topPanel.setHidden(perspectiveHidesMenu || prefHidesMenu);
+
+        const perspectiveHidesStatus = descriptor.chromeOptions?.hideStatusBar ?? false;
+        const prefHidesStatus = !this.preferenceService.get<boolean>(
+            'workbench.statusBar.visible', true
+        );
+        this.statusBar.setHidden(perspectiveHidesStatus || prefHidesStatus);


This reimplements chrome handling that already lives in the shell and status bar, and both keep managing the same targets. The menu-bar branch duplicates ApplicationShell.setTopPanelVisibility (

theia/packages/core/src/browser/shell/application-shell.ts

Lines 417 to 419 in a332678

protected setTopPanelVisibility(preference: string): void {

const hiddenPreferences = ['compact', 'hidden'];

this.topPanel.setHidden(hiddenPreferences.includes(preference));

), and the status-bar branch fights StatusBarImpl's own preference listener (

theia/packages/core/src/browser/status-bar/status-bar.tsx

Lines 57 to 61 in a332678

this.preferences.onPreferenceChanged(preference => {

if (preference.preferenceName === 'workbench.statusBar.visible') {

this.setHidden(!this.preferences.get('workbench.statusBar.visible', true));

}

})

). Since the shell also listens to window.menuBarVisibility (

theia/packages/core/src/browser/shell/application-shell.ts

Lines 342 to 346 in a332678

this.setTopPanelVisibility(this.corePreferences['window.menuBarVisibility']);

});

this.corePreferences.onPreferenceChanged(preference => {

if (preference.preferenceName === 'window.menuBarVisibility') {

this.setTopPanelVisibility(this.corePreferences['window.menuBarVisibility']);

), a preference change makes both set topPanel hidden and the result depends on listener order. Better to route through the shell rather than set topPanel/statusBar directly here.

sdirix

See comments

sdirix · 2026-07-07T11:55:51Z

+
+    setMenuBarHiddenByPerspective(hidden: boolean): void {
+        this.perspectiveHidesTopPanel = hidden;
+        this.setTopPanelVisibility(this.corePreferences['window.menuBarVisibility']);


On Electron this likely has no effect: the shell only wires top-panel visibility for non-Electron (init guards these setTopPanelVisibility calls with !environment.electron.is(),

theia/packages/core/src/browser/shell/application-shell.ts

Lines 340 to 346 in a332678

if (!environment.electron.is()) {

this.corePreferences.ready.then(() => {

this.setTopPanelVisibility(this.corePreferences['window.menuBarVisibility']);

});

this.corePreferences.onPreferenceChanged(preference => {

if (preference.preferenceName === 'window.menuBarVisibility') {

this.setTopPanelVisibility(this.corePreferences['window.menuBarVisibility']);

) and Electron uses a native menu, so AI First's hideMenuBar won't hide the menu there.

sdirix · 2026-07-07T11:55:53Z

+import { EXPLORER_VIEW_CONTAINER_ID } from '@theia/navigator/lib/browser';
+import { SCM_VIEW_CONTAINER_ID } from '@theia/scm/lib/browser/scm-contribution';
+
+const CHAT_VIEW_WIDGET_ID = 'chat-view-widget';


ai-ide already depends on @theia/ai-chat-ui, so this could import ChatViewWidget.ID (

theia/packages/ai-chat-ui/src/browser/chat-view-widget.tsx

Line 42 in a332678

public static ID = 'chat-view-widget';

) instead of hardcoding the string.

CamilleLetavernier · 2026-07-07T14:52:36Z

Thanks for the review!

I updated the PR to address the comments. I removed menu bar visibility option as it's a bit tedious to consistently support, due to the several different options. Also, we likely want to "filter" menus rather than "hide" them entirely.

sdirix

One minor comment. COuld be adressed in a follow up

sdirix · 2026-07-07T15:20:38Z

+        if (this.switchInProgress) {
+            await this.switchInProgress;
+        }
+        this.switchInProgress = this.doSwitchPerspective(id);


The added guard serializes two switches but not three or more: a third concurrent caller resumes from the same await this.switchInProgress and then reassigns switchInProgress to its own doSwitchPerspective, so it runs concurrently with the second one and their savedLayouts writes can still interleave. Chaining instead would fully serialize, e.g. this.switchInProgress = (this.switchInProgress ?? Promise.resolve()).then(() => this.doSwitchPerspective(id)).

sdirix · 2026-07-07T16:04:56Z

+
+        const savedLayout = this.savedLayouts.get(id);
+        if (savedLayout) {
+            await this.shell.setLayoutData(savedLayout);


activePerspectiveId is already advanced at L148, but setLayoutData here (and collapsePanel below) aren't guarded like the widget loop is. If either rejects, the service reports the new perspective as active while its layout was never applied, and since switches are chained the rejection also drops any switch queued behind it. A try/catch around the layout application would keep the state consistent. Fine as a follow-up.

CamilleLetavernier added 3 commits July 7, 2026 09:35

feat: add a perspective service + AI First perspective

be6e41f

feat: add default perspective; restore perspective state on switch

3a97354

feat: add chrome-visibility options on perspectives

98b71c8

CamilleLetavernier requested a review from sdirix July 7, 2026 09:05

CamilleLetavernier marked this pull request as draft July 7, 2026 09:06

CamilleLetavernier changed the base branch from master to ai-first July 7, 2026 09:09

CamilleLetavernier marked this pull request as ready for review July 7, 2026 09:09

sdirix reviewed Jul 7, 2026

View reviewed changes

feat: rename Theia IDE perspective to 'Default'

deb6dd4

sdirix reviewed Jul 7, 2026

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Comment thread packages/core/src/browser/shell/view-contribution.ts Outdated

CamilleLetavernier added 2 commits July 7, 2026 12:21

fix: address review comments

637f209

feat: do not rely on view-contribution for perspective management

ae98b0c

sdirix reviewed Jul 7, 2026

View reviewed changes

CamilleLetavernier added 2 commits July 7, 2026 15:31

fix: address review comments

2183211

feat: remove menu bar filtering

3a65649

CamilleLetavernier requested a review from sdirix July 7, 2026 14:51

sdirix approved these changes Jul 7, 2026

View reviewed changes

fix: properly chain perspective switching promises for consistency

91bc4b0

CamilleLetavernier requested a review from sdirix July 7, 2026 15:54

sdirix approved these changes Jul 7, 2026

View reviewed changes

CamilleLetavernier merged commit 3a42dc2 into ai-first Jul 7, 2026
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feat: explore perspective mechanisms - #320

feat: explore perspective mechanisms#320
CamilleLetavernier merged 9 commits into
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issues/283-perspective

CamilleLetavernier commented Jul 7, 2026 •

edited

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	protected setTopPanelVisibility(preference: string): void {
	const hiddenPreferences = ['compact', 'hidden'];
	this.topPanel.setHidden(hiddenPreferences.includes(preference));

	this.preferences.onPreferenceChanged(preference => {
	if (preference.preferenceName === 'workbench.statusBar.visible') {
	this.setHidden(!this.preferences.get('workbench.statusBar.visible', true));
	}
	})

	this.setTopPanelVisibility(this.corePreferences['window.menuBarVisibility']);
	});
	this.corePreferences.onPreferenceChanged(preference => {
	if (preference.preferenceName === 'window.menuBarVisibility') {
	this.setTopPanelVisibility(this.corePreferences['window.menuBarVisibility']);

	if (!environment.electron.is()) {
	this.corePreferences.ready.then(() => {
	this.setTopPanelVisibility(this.corePreferences['window.menuBarVisibility']);
	});
	this.corePreferences.onPreferenceChanged(preference => {
	if (preference.preferenceName === 'window.menuBarVisibility') {
	this.setTopPanelVisibility(this.corePreferences['window.menuBarVisibility']);

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What it does

How to test

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CamilleLetavernier commented Jul 7, 2026 •

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