Rosegarden is uninstallable, at least on my Sid system. I get the following error message when running apt-get install rosegarden:The following packages have unmet dependencies. rosegarden: Depends: kdebase-bin but it is not going to be installed E: Broken packages
I tried and failed to reproduce this so I suspect it was just a transiant issue (transiant uninstallability is normal in sid, it is only if it goes on for some time that it is worth a bug report).
If you can still reproduce it could you try adding the packages it says won't be installed to the install command line until you get a more usefull error message out of apt?