Python Add-In does not report to python window

Hi,

I just began to take a look at the Python Add-Ins. Simple tests with buttons and tools do work, after normal installation. But in my case the Add-Ins do not report any information to the python window (ArcMap 10.1). So the debugging as described in the ArcGIS Help “guidebook” by sending “exceptions” as well as using the “print” statement does not work at all.
Does anyone have an idea what the reasons could be?

Thanks for any help