src/vs/workbench/browser/parts/editor/editorPart.ts/EditorPart/doRemoveEmptyGroup
class EditorPart:	private doRemoveEmptyGroup(groupView: IEditorGroupView): void {
		const restoreFocus = this.shouldRestoreFocus(this.container);

		// Activate next group if the removed one was active
		if (this._activeGroup === groupView) {
			const mostRecentlyActiveGroups = this.getGroups(GroupsOrder.MOST_RECENTLY_ACTIVE);
			const nextActiveGroup = mostRecentlyActiveGroups[1]; // [0] will be the current group we are about to dispose
			this.activateGroup(nextActiveGroup);
		}

		// Remove from grid widget & dispose
		this.gridWidget.removeView(groupView, this.getSplitSizingStyle());
		groupView.dispose();

		// Restore focus if we had it previously (we run this after gridWidget.removeView() is called
		// because removing a view can mean to reparent it and thus focus would be removed otherwise)
		if (restoreFocus) {
			this._activeGroup.focus();
		}

		// Notify group index change given a group was removed
		this.notifyGroupIndexChange();

		// Update container
		this.updateContainer();

		// Event
		this._onDidRemoveGroup.fire(groupView);
	}