This is the intended behavior of the RibbonBar. When the ribbon is collapsed and you click on a tab, the ribbon is temporarily expanded, so that you can see the contents of the tab, and clicking outside the ribbon will collapse it again. If you click on the minimize arrow while it's temporarily expanded you will permanently expand the ribbon.
This is the same behavior as in MS Word, as you can verify yourself.
Regards,
Bozhidar
Telerik
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