PySolFC on CentOS 7: Tk Errors

So you either built it from SRPMs or simply got the necessary libraries and got the source. Either way, you’ve got PySolFC on your CentOS/RHEL 7 machine and it won’t work. If you try to launch it from the CLI, here’s the error:

Traceback (most recent call last):
  File "pysol.py", line 26, in 
    init()
  File "/home/ed/src/PySolFC-2.0/pysollib/init.py", line 120, in init
    root = Tkinter.Tk(className=settings.TITLE)
  File "/usr/lib64/python2.7/lib-tk/Tkinter.py", line 1745, in __init__
    self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: unknown color name "BACKGROUND"

I fought with this for hours and no one wants to answer the question as to what causes this. Finally, I discerned it’s a problem with no defaults for Tk interface elements. The color “BACKGROUND” is defined in the default theme. Most Linux distros work this out for you through various system scripts and settings. It’s not included in the packages you can get or build on CentOS 7. The answer is to create a dot-file in your home directory: .Xdefaults. You’ll need one line in it:

TkTheme: clearlooks

Save the file and run this command:

xrdb -load .Xdefaults

Try again to launch PySolFC. It should work now. Remember that you’ll have to reload that on every login.