Is there any way to force an application to use a certain window theme? ie: LMMS (attachment)

I hate having the huge cluttered UI like LMMS and JACK Control have. It's like QT3 and it's all big, etc.

Is there any way to force LMMS to use the default UI that, say, Firefox uses (GTK2)?

yeah its just the way things are, some apps just dont like it. e.g some gnome GTK apps look really wierd in KDE

Is there any way to change it?

It's because of one of the greatest and worst things about Linux: there is no one single UI library, and developers will tend to develop their user interface for whatever window manager they prefer best.. What I suspect you're seeing is a QT application running on Gnome. Because you aren't running KDE, QT has no themes to use, and thus you get the default ugly title bars. The reason that LMMS looks so good in the last screenshot you posted is because it's running on a KDE interface. I'm reasonably sure that it's possible to use QT themes within Gnome, although an easier approach would probably be to use something like QTGnome.


I booted up, checked my system updates (I had notifications off, for some stupid reasons) and updated my 232 updates.

Now it works, looks normal. I didn't install qtgnome either.