src/vs/workbench/browser/parts/activitybar/activitybarPart.ts/ActivitybarPart/getVisibleViewContainerIds
class ActivitybarPart:	getVisibleViewContainerIds(): string[] {
		return this.compositeBar.getVisibleComposites()
			.filter(v => this.viewsService.getVisibleViewContainer(this.location)?.id === v.id || this.compositeBar.isPinned(v.id))
			.map(v => v.id);
	}