Ubuntu – When I use gimp cage transform but it crashes

there's a weird error in GIMP that causes the crash.

you have to goto your System Settings > Application Appearance > GTK+ Appearance and change the Widget style to Raleigh.

now start GIMP once and you can change the the GTK+ style back to whatever you want

weird but it works

as for your other issues, try adding the kubuntu ppa's to you repos as there are monthly updates that sort out many of the issues you're having, especially with amarok

Firstly remove the Gimp 2.8 repository by running these commands:

sudo apt-get install ppa-purge
sudo ppa-purge ppa:otto-kesselgulasch/gimp

and then run:

sudo apt-get update

Now remove the plugin-registry as it is not supported on 2.8:

sudo apt-get remove gimp-plugin-registry

Once that's done you can install Gimp 2.8:

sudo add-apt-repository ppa:otto-kesselgulasch/gimp
sudo apt-get update
sudo apt-get install gimp