Revert "sessions: hide disabled chat input pickers (#307494)"

[sandy081]

This reverts commit c2f1a6e.

[Copilot]

Pull request overview

Reverts prior sessions UI behavior that hid certain chat input “picker” controls when they were disabled, restoring visibility (with disabled styling/behavior) and removing the CSS that suppressed shared workbench pickers in the sessions app.

Changes:

• Switch multiple picker widgets from dom.setVisibility(...)/aria-hidden behavior to a disabled state via CSS class toggling.
• Remove sessions CSS that hid .chat-sessionPicker-container in the sessions workbench.
• Remove/adjust menu when gating and delete picker-specific browser tests that no longer match the updated behavior.

Show a summary per file

File	Description
src/vs/sessions/contrib/copilotChatSessions/test/browser/branchPicker.test.ts	Removes BranchPicker tests (previous expectations no longer apply).
src/vs/sessions/contrib/copilotChatSessions/browser/modePicker.ts	Stops hiding mode picker; uses disabled styling instead.
src/vs/sessions/contrib/copilotChatSessions/browser/modelPicker.ts	Stops hiding model picker; uses disabled styling instead.
src/vs/sessions/contrib/copilotChatSessions/browser/isolationPicker.ts	Stops hiding isolation picker; uses disabled styling instead.
src/vs/sessions/contrib/copilotChatSessions/browser/copilotChatSessionsActions.ts	Removes IsNewChatSessionContext gating for some new-session menus.
src/vs/sessions/contrib/copilotChatSessions/browser/branchPicker.ts	Disables branch picker in more cases instead of hiding it.
src/vs/sessions/contrib/chat/test/browser/sessionTypePicker.test.ts	Removes SessionTypePicker tests (previous hide/show expectations no longer apply).
src/vs/sessions/contrib/chat/browser/sessionTypePicker.ts	Stops hiding session type picker; uses disabled styling instead.
src/vs/sessions/browser/media/style.css	Removes CSS rule that hid shared chat session pickers in sessions workbench.

Copilot's findings

Comments suppressed due to low confidence (1)

src/vs/sessions/contrib/chat/browser/sessionTypePicker.ts:134

• The PR changes picker behavior (e.g. SessionTypePicker no longer uses dom.setVisibility and relies on a disabled state instead), but the corresponding browser tests for these pickers were removed rather than updated. Please add/adjust unit tests to cover the new disabled/visible behavior and the associated accessibility attributes (aria-disabled, tabIndex) to prevent regressions.

	private _updateTriggerLabel(): void {
		if (!this._triggerElement) {
			return;
		}

		dom.clearNode(this._triggerElement);

		const currentType = this._sessionTypes.find(t => t.id === this._sessionType);
		const modeIcon = currentType?.icon ?? Codicon.terminal;
		const modeLabel = currentType?.label ?? this._sessionType ?? '';

		dom.append(this._triggerElement, renderIcon(modeIcon));
		const labelSpan = dom.append(this._triggerElement, dom.$('span.sessions-chat-dropdown-label'));
		labelSpan.textContent = modeLabel;

		const hasMultipleTypes = this._sessionTypes.length > 1;
		this._slotElement?.classList.toggle('disabled', !hasMultipleTypes);
		dom.append(this._triggerElement, renderIcon(Codicon.chevronDown));
	}

• Files reviewed: 9/9 changed files
• Comments generated: 4

[Copilot]

_updateTriggerLabel marks the picker as disabled when modes.length <= 1, but the trigger remains focusable (tabIndex stays 0) and _showPicker() doesn’t check this disabled condition. Because .disabled only sets pointer-events: none, keyboard users can still open the picker (and it will open) despite the UI indicating it’s disabled. Consider setting aria-disabled + tabIndex=-1 when disabled and/or early-returning in _showPicker() when there’s no selectable mode choice (to keep behavior consistent across mouse/keyboard and for accessibility).

Suggested change

	this._slotElement?.classList.toggle('disabled', modes.length <= 1);
	const isDisabled = modes.length <= 1;
	this._slotElement?.classList.toggle('disabled', isDisabled);
	this._triggerElement.setAttribute('aria-disabled', isDisabled ? 'true' : 'false');
	this._triggerElement.tabIndex = isDisabled ? -1 : 0;

[Copilot]

When there are no models, the slot gets the disabled class and aria-disabled is set, but the trigger remains in the tab order (tabIndex is never updated). Since the disabled styling uses pointer-events: none, the element can still receive focus via keyboard, which is inconsistent with a disabled control. Consider setting tabIndex=-1 when this._models.length === 0 (and restoring to 0 when models exist).

Suggested change

	this._slotElement?.classList.toggle('disabled', this._models.length === 0);
	this._triggerElement.setAttribute('aria-disabled', String(this._models.length === 0));
	const isDisabled = this._models.length === 0;
	this._slotElement?.classList.toggle('disabled', isDisabled);
	this._triggerElement.setAttribute('aria-disabled', String(isDisabled));
	this._triggerElement.tabIndex = isDisabled ? -1 : 0;

[Copilot]

_updateTriggerLabel now only toggles the disabled class when there’s a single session type, but it no longer sets aria-disabled or removes the trigger from the tab order. This makes the control appear disabled while still being keyboard-focusable. Consider updating aria-disabled and tabIndex alongside the disabled class to match the behavior in other pickers (e.g. BranchPicker/IsolationPicker).

This issue also appears on line 116 of the same file.

Suggested change

	this._slotElement?.classList.toggle('disabled', !hasMultipleTypes);
	this._slotElement?.classList.toggle('disabled', !hasMultipleTypes);
	this._triggerElement.setAttribute('aria-disabled', String(!hasMultipleTypes));
	this._triggerElement.tabIndex = hasMultipleTypes ? 0 : -1;

[Copilot]

The picker’s interaction is gated on both _hasGitRepo and _isolationOptionEnabled in _showPicker(), but _updateTriggerLabel() only disables the UI when _hasGitRepo is false. If the isolation option gets disabled via configuration while the widget is rendered, the control can appear enabled yet do nothing. Consider including !this._isolationOptionEnabled in the disabled state (class, aria-disabled, and tabIndex) to keep the UI consistent with behavior.