Out of sync when closing subwindow that opened tableexporter download dialo

Hello,

Closing a subwindow (opened from another subwindow, both modal) first is not removed, on second attempt results in “out of sync” message.
This is only happens when the download dialog of tableexporter addon is opened by the user from the subwindow in question.
Until no download dialog is opened no problem with subwindow closing either using the default closing icon or my close button.

Any idea why this happens and how to solve?

Thanks!
Zsolt

Since then found the (
table export
thread, so I move this question to there.