I'm using a RadPanelBar as a categorized menu, where the headers are the categories and the children of the headers are the menu items. If you look at the screenshot of the RadPanelBar in your documentation at http://docs.telerik.com/devtools/wpf/controls/radpanelbar/structure, that's pretty much what I want it to look like.
However, using the latest version (R3 2016), a basic RadPanelBar looks very different from the screenshot in your documentation. I've attached a screen shot and here is my xaml:
<telerik:RadPanelBar Grid.Row="1" ExpandMode="Multiple" >
<telerik:RadPanelBarItem Header="Security" IsExpanded="True">
<TextBlock Text="Rights By User" />
<TextBlock Text="Rights By Right" />
</telerik:RadPanelBarItem>
</telerik:RadPanelBar>
The differences I don't like are (1) the items are indented by what looks like about 60px, and (2) the items stretch to fill the available vertical space. I want the items to not be indented and to be their natural height, as they are in your screen shot.
I'm using the VisualStudio2013 theme, which might account for the difference. If that's it, could you give me some guidance on where that margin/padding that causes the indent is coming from? I've skimmed the templates in the theme and didn't see it.