Hi Slava,
To prevent this problem you need to have an appropriately named Toolbar in your MainFrameBarManager. The Child needs a matching Toolbar to merge its BarItems into. You don''t need to populate this Toolbar with any BarItems, but it does need to be created by the MainFrameBarManager.
I fixed the problem in your sample by creating a Toolbar named MainToolBar in Form1. I''ve run it through my own Memory Profiler and the memory appears to be freed now.
Regards,
Gregory Austin
Syncfusion, Inc.
SyncMemoryLeak_5240.zip