src/vs/workbench/browser/parts/views/viewPaneContainer.ts/ViewPaneContainer/getActionViewItem
class ViewPaneContainer:	getActionViewItem(action: IAction): IActionViewItem | undefined {
		if (this.isViewMergedWithContainer()) {
			return this.paneItems[0].pane.getActionViewItem(action);
		}
		return createActionViewItem(this.instantiationService, action);
	}