select model when sub menu value is selected

[sandy081]

fixes

#304120
#303570
#304017

[Copilot]

Pull request overview

This PR adjusts the ActionWidget action list submenu behavior and styling to improve model-picker submenu interactions (notably around “Thinking/Reasoning effort”), addressing the reported model picker dismissal/interaction issues.

Changes:

• Switch submenu activation from chevron hover/click to row hover (with a delay) and adjust submenu anchoring/positioning to avoid overlap issues.
• When a submenu action is selected, also select the parent item in the main list (so submenu changes don’t effectively “drop” the parent selection flow).
• Tweak action widget row/filter spacing and submenu-indicator styling to reduce visual overlap and improve layout.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/vs/platform/actionWidget/browser/actionWidget.css	Adjusts row/filter spacing and submenu-indicator styling to reduce overlap and improve alignment.
src/vs/platform/actionWidget/browser/actionList.ts	Changes submenu trigger mechanics (row-hover + delay), positions submenu relative to the row, and selects the parent item when a submenu action is chosen.

Comments suppressed due to low confidence (1)

src/vs/platform/actionWidget/browser/actionList.ts:1420

• With the removal of the submenu-indicator click/hover wiring, clicking on the chevron area no longer opens the submenu, and selection is still suppressed for clicks targeting .action-list-submenu-indicator (see onListSelection). This makes a click on the indicator effectively a no-op. Consider either reintroducing an explicit click handler to open the submenu immediately, or removing/relaxing the selection-suppression for indicator clicks now that the indicator is not interactive.

	private onListClick(e: IListMouseEvent<IActionListItem<T>>): void {
		if (e.element && e.element.isSectionToggle && e.element.section) {
			const section = e.element.section;
			queueMicrotask(() => this._toggleSection(section));
			return;
		}
		if (e.element && this.focusCondition(e.element)) {
			this._list.setFocus([]);
		}