I have placed a RadRibbonView inside a prism region.
Neither the region nor the RadRibbonView have an explicit Height set. Clicking the ApplicationMenu Button, to expose the Backstage, will cause the issue described in the attached image.
The Backstage won't expand to ocuppy the whole window size, it will instead look as though it's trapped inside the region.
I came up with a temp workaround: Adding Height="143"
to the region, and adding in the code behind:
MyRibbonView.Height = SystemParameters.WorkArea.Height;
will solve the problem, but will cause unexpected behavior in, for example, the help ScreenTips.
I found a post claiming that adding
inside the region will make it expand when needed and solve the problem, but it does not, and makes the whole region content disappear, also.