If you have a RadComboBox inside a ControlPanelItem, when you open the RadComboBox's dropdown and select an item, the ControlPanelItem is not closed. As a workaround, you can manually capture the mouse. Please check the attached project.

Grouping of columns in RadGridView by using a ColumnGroupDescriptor in XAML does not work when ShowGroupPanel is set to False and there is a RelativeSource binding in the ColumnGroupDescriptor.

Hello

Good job with the Fluent theme! I'm using the core styles with validation in my GridViews and have noticed that the bottom border is not/barely visible in invalid grid cells (see attached screenshot).

I can fix this by taking a copy of GridViewCellCoreValidationTemplate and adding Margin="0 0 0 1" to Background_Invalid.

Cheers
Jack