Hi Zoltan,
Thanks for the update.
Argument Exception: when user switches tabs or forms very quickly.We are still not able to reproduce the issue, we tried repeat to switching between the tabs and forms, but not able to reproduce the issue.
Please take a look into the video file for your reference:
http://websamples.syncfusion.com/samples/Tools.Windows/F47438/main.htmCould you please modify the sample or provide your sample to reproduce the issue, so that we can be able to reproduce the issue and investigate further on this issue and could you please provide your system configuration too.
Please let me know if you have any other questions.
Best Regards,
Bhuvana