src/vs/platform/undoRedo/common/undoRedoService.ts/ResourceEditStack/pushElement
class ResourceEditStack:	public pushElement(element: StackElement): void {
		// remove the future
		for (const futureElement of this._future) {
			if (futureElement.type === UndoRedoElementType.Workspace) {
				futureElement.removeResource(this.resourceLabel, this.strResource, RemovedResourceReason.NoParallelUniverses);
			}
		}
		this._future = [];
		this._past.push(element);
		this.versionId++;
	}