src/vs/workbench/services/history/browser/historyService.ts/EditorNavigationStack/registerGroupListeners
class EditorNavigationStack:	private registerGroupListeners(groupId: GroupIdentifier): void {
		if (!this.mapGroupToDisposable.has(groupId)) {
			const group = this.editorGroupService.getGroup(groupId);
			if (group) {
				this.mapGroupToDisposable.set(groupId, group.onWillMoveEditor(e => this.onWillMoveEditor(e)));
			}
		}
	}