src/vs/workbench/browser/parts/views/viewPaneContainer.ts/ViewPaneContainer/removePanes
class ViewPaneContainer:	removePanes(panes: ViewPane[]): void {
		const wasMerged = this.isViewMergedWithContainer();

		panes.forEach(pane => this.removePane(pane));

		this.updateViewHeaders();
		if (wasMerged !== this.isViewMergedWithContainer()) {
			this.updateTitleArea();
		}

		this._onDidRemoveViews.fire(panes);
	}