src/vs/workbench/browser/parts/panel/panelPart.ts/BasePanelPart/getToolbarWidth
class BasePanelPart:	protected getToolbarWidth(): number {
		const activePanel = this.getActivePaneComposite();
		if (!activePanel || !this.toolBar) {
			return 0;
		}

		return this.toolBar.getItemsWidth() + (this.globalToolBar?.getItemsWidth() ?? 0);
	}