Comment 34 for bug 144175

Found a better workaround !!!

Remove the tilda which come from gutsy (it is bugged)
and install this one :
http://macsim.labolinux.net/upload/tilda_0.09.4-0ubuntu2.1_i386.deb
(it was builded (not me!!) in the past, when "true transparency patch" was tested in tilda)

for me : it's work like a charm .... hope for you too ;