Changing Themes in TKabber
Locate the appropriate ‘config.tcl’ file. On Linux, it’s probably in ~/.tkabber/ on Windows look into %APPDATA%/TKabber or %TKABBER_HOME%.
Open the ‘config.tcl’ in the texteditor of your choice.
Add or modify this line to specifiy the theme (.xrdb file) you want:
option readfile ~/.tkabber/Cargal.xrdb userDefault
Easy, but I always forget it. Thanks to Lotussteve for the pointer.