Colors panel issue in Gemas

[Germán Arias]

In revision 49 of Gemas.app when I open the Preferences panel and then 
the colors panel,
the opened document is marked as edited. I can't reproduce this 
problem with other app.
To solve this, now I launch the preferences panel in modal. I don't 
understand why opening the
colors panel change the document. But I hope not to be an error in 
gnustep.