This bug is in R# since v7, maybe it was there even in v6, not sure.When pasting code into xaml file, sometimes the missing namespaces are are not recognized properly and I have to add them manually.
How to reproduce this scenario:
Create new empty Windows Phone 7 project. There is already empty MainPageAdd new Pivot page.
Copy the <Grid>...</Grid> from the Pivot page and paste it into the Main page instead of the original Grid tag.
dialog for adding missing namespaces shows up,I press Alt-Enter, I expect missing namespace is added for the controls:Pivot and controls:PivotItem
when I press Alt + Enter, it changes these tags to phone:Pivot and phone:PivotItem where phone is
but is should instead add the namespace
Tested in VS2012 and WP8 SDK beta with WP7 project, but it should be reproducible in VS2010 and WP7 SDK too, maybe it's problem in WPF, Silverlight and WinRT projects as well.