Theme color doesn't get hex format correctly, and themes should change backgroud color
The theme manager Pick a Color->Color Name input text get the right color, but in real gajim screen it appears bad.
Try this color #0F0000
and you'll get #F00000
. It seems to skip the initial 0 from every component. I suppose it's a failure on the hex parser. Nothing very difficult to solve.
An nobody can change the default white color from buddies window, a thing important for themes. I was trying a dark theme, and with that white it looks more than terrible.