Hi Zvonko,
Thanks for your interest in Syncfusion Products.
I am afraid that I could not able to reproduce the issue of Hidden rows problem as you mentioned above. Could you please provide an issue reproduced sample or the reproducing steps so that we can sort out the problem and direct you to the exact solution on time??
Sample:
http://websamples.syncfusion.com//samples/Grid.Windows/Development/GC_HideRows_F79260.zipPlease let me know if this helps and provide more information on this issue.
Regards,
Nisha.