Invoking any form that changes the class while an instance of it is running causes stability issues and leads to unpredictable behaviour in the widget. This is most likely due to the C++ side not liking the change. If there isn't any way to fix this, there should at least be a test for whether a given option already exists properly on the class as expected by the form, and if so, no change should be made. This should cover most of the cases of redefinition.
This is "fixed" for now by, as mentioned above, only setting class options when absolutely necessary, but it would be much better if the instability could not be caused at all.
Invoking any form that changes the class while an instance of it is running causes stability issues and leads to unpredictable behaviour in the widget. This is most likely due to the C++ side not liking the change. If there isn't any way to fix this, there should at least be a test for whether a given option already exists properly on the class as expected by the form, and if so, no change should be made. This should cover most of the cases of redefinition.