For the benefit of other users, I am providing the following feedback on this problem which I raised some weekes ago.
After considerable experimentation, I discovered that by not using the ‘theme’ setting in the treegrid widget (which I was applying in the context of the tab) the problem was resolved.
By ‘not using’ I mean that the theme setting is simply not present in the settings collection. (Note: By setting the theme value to ” i.e. empty string – did not remove the problem.
Interestingly, I am also using a grid widget in a different tab setting, and I did not have to disable the theme setting. It worked fine.
Friendly regards,
Alastair