Editor crash when deleting forms

[fmfdario <fmfdario@xxxxxxxxx>]

Hi everyone. Merry Christmas and Happy New Year!.

When I'm testing the functionality of a project, I import the form I'm 
working on

and work with the new one. This way I don't mess up the old one.

I select the new form as the startup class. This way up to x's forms.

Once I have the project working as I want. I delete forms to keep only 
the one I'm interested in.
During this process the editor can show an error message like this:

"This application has raised an unexpected error and must aborted"
"[29] object invalid"
"FFormStack.SelectCurrent.235"

When I exit, the last deleted form loses its form nature
and becomes a plain class.

I'm using the stable version 3.19.5 and my system is
Linux Mint Mate 21.1

I hope the images can be seen correctly.

Thank you.

Attachment: Occasional_error_ when_deleting_a_ form.png
Description: PNG image

Attachment: Project_status_after_the_error.png
Description: PNG image