Libre Office Base Form v6.4.6.2 crashes "Object has been already disposed" Ubuntu 18.04

Libre Office Base Form editor often crashes when pasting a copied control such as a text box, label or listbox. I also noticed that sometimes a complete group of controls are removed randomly. In this case, undo does not work and sometimes it requests to send an error report. It is not always reproducible.

This also happens when:

  • Change font of a multi-line textbox
  • Select another control on the form

Error message pops-up “Object has been already disposed” and LibreOffice crashes. Last form changes are lost:

Object-has-been-already-disposed.png

I’m using the latest LO v6.4.6.2 on Ubuntu 18.04. How can this be fixed?

(Edit: activated screenshot -AK)