Hi Oleg,
I am afraid that I am not able to reproduce the issue of first button(baritem) being removed from the XPToolBar having 3 buttons when the window is resized horizontally with the attached sample.
Could you please modify the attached sample so that the issue could be reproduced? This will help us to resolve the issue soon.
We appreciate your interest in Syncfusion products.
http://websamples.syncfusion.com/samples/Tools.Windows/F61808/Main.htmBest regards,
Golda