VS 2015 RC1 - Most Recend Used List broken

I'm currently working on my extension (a custom start page) to get it ready for the Visual Studio 2015 release.

I found an issue regarding the MRU list, a control provided by Microsoft - it seems to be partially broken.
I already created a issue on GitHub for this on the project side (https://github.com/Herdo/SolutionStartPage/issues/5), but I'll explain it here, too:

The MRU list is displaying the recent projects/solutions correctly, and also the context menus of the single entries are displaying. However, neither the context menu item to open the solution or to open the directory are working.

The worst: Even just clicking on any item in the MRU list doesn't open the reffered solution.

The code for the MRU list is the same as in the 2013 version:

xmlns:platformUi="clr-namespace:Microsoft.VisualStudio.PlatformUI;assembly=Microsoft.VisualStudio.Shell.12.0"

...

<platformUi:MruListBox Grid.Row="1"
                       Margin="-28,0,0,0"
                       DataContext="{Binding RecentProjects}"
                       ItemsSource="{Binding Path=Items}"
                       Background="Transparent"
                       BorderThickness="0"
                       AutomationProperties.AutomationId="MruList"/>