src/vs/workbench/api/browser/mainThreadEditorTabs.ts/MainThreadEditorTabs/$closeGroup
class MainThreadEditorTabs:	async $closeGroup(groupIds: number[], preserveFocus?: boolean): Promise<boolean> {
		const groupCloseResults: boolean[] = [];
		for (const groupId of groupIds) {
			const group = this._editorGroupsService.getGroup(groupId);
			if (group) {
				groupCloseResults.push(await group.closeAllEditors());
				// Make sure group is empty but still there before removing it
				if (group.count === 0 && this._editorGroupsService.getGroup(group.id)) {
					this._editorGroupsService.removeGroup(group);
				}
			}
		}
		return groupCloseResults.every(result => result);
	}