Although it looks like an issue, actually the behavior is expected. We have fixed an issue in Q1 SP and since then the unpined Panes can not go beyond RadDocking layout, which should be the correct behavior. So in this case the width of the RadDocking is constrained by the width of the Grid's column and therefore the unpined Pane is smaller.
I am not sure about the layout of your application, but it seems like you can use DocumentHost and achieve the same thing. In the attached project you can see how to implement that. What I have basically done is:
- Set Visibility="Collapsed" CanUserClose="False" to the RadPane into the DocumentHost.
- Delete the 3 borders into the PaneGroup_DocumentFrameTemplate - BorderLayer1, BorderLayer2, BorderLayer3
Hope this will help.
All the best,
the Telerik team
Explore the entire Telerik portfolio by downloading the Ultimate Collection trial package. Get it now >>