RibbonView: The DropDownPopupContent inside RadRibbonDropDownButton has a default FocusVisualStyle
As a workaround, you can set the FocusVisualStyle of the DropDownPopupContent element in the template of the RadRibbonDropDownButton to null or add an implicit style for ContentControl setting the FocusVisualStyle to null.
Posted on:24 Aug 2018 12:48
The fix for the issue will be available in next LIB version (2018.2.827) which it is uploaded on August 28, 2018. It will also be included in our official version – R3 2018, scheduled for the mid of September.