Problem with removing a user widget

Hello. I have some widget in Slate (SMyVerticalBox). This widget is associated with another, inherited from UCanvasPanel. I’m adding that widget to a main canvas panel of a third widget, created in UMG.
That widget represents some interactive menu. When I call “Remove from parent” for this menu in some BP code, and then, some time after that, I create this menu again and add it to a viewport, code of my old menu continues its execution.
What’s may be wrong?