Hey, Ali! Thank you 1000x for your detailed answer! The most important hint was "open Chrome". Besides stating "A turbulence detected!" after logging in, it works flawlessly! I normally use Opera which obviously doesn't like Wave out of the box. However, after picking "mask as Firefox" in the settings, it is happy with showing my inbox. Problem solved, thank you very much! Now it's time for me banging my head on the next wall...
Just a small second question: which packages do I need to install to compile Wave? Even with ant, openjdk, mercurial and eclipse it wouldn't compile on openSUSE. No problems on Debian however. Best wishes, Jan-Philipp
