This could happen if VeSys is unable to write to the configuration files. I would check that you have permission to write to those files or that they haven't been set to 'Read Only'.
I can change the drawing colours. I changed the wires default colour and the simulation default colour and these have stayed changed.
That is strange that you are able to edit some of the fields because all the data is stored in the same file. Although its unorthodox you could manually edit the colors in the VeSysDesign.ini file which is located in your configuration folder, if you are not comfortable doing this you could e-mail it to me and I'll update it for you. If you would like me to do this I would need a copy of your ini file along with the list of the Colors required and their RGB values i.e. B = 0,0,0
Thanks for that tip, it worked and I now have my colours back. I looked in "VeSysDesign_Template.ini" and copied the structure and colours.
I then tried to add a new colour in the configuration editor, saved, exited and went back in. The new colour had saved ok.
I'm not sure why manually adding them fix it, maybe if you save the configuration with 0 or mininal colors it causes a problem.
Anyway the important thing is that your issue is resolved.