While compiling my VB solution i noticed that some code in the editor window was marked as error by R#. As compiling was finished the errors where removed. I had triggered a rebuild of the solution and the errors where shown for some function calls on a self written User-Control. This behavior is reproducable for each rebuild. It seems that R# looses information about the user control at the time it was deleted in the rebuild process.
As some other people mentioned preformance loss on compiling when using R# i consider if it should be possible to suspend R# code analysis while compiling code. This may result in a performance boost.