Hello, it appears that the pattern option gets set no matter what when applying a theme, even when applying a theme which does not use a pattern. For example, try "Scaled Black Theme" or "Art of Dark Cappuccino" from http://wiki.awn-project.org/index.php?title=Themes. When you apply them, you have to go to the General tab, then "Pattern Engine", and disable the "Enable pattern" checkbox. If it was previously disabled, you will have to check it and then uncheck it. Otherwise just uncheck it. Now the theme will display correctly, with separators and proper gradients, borders, etc.
You can even go right back to the Themes tab, and click Apply again on the very same theme, and it will enable the pattern again and you will have to go back and do this again.
I have noticed this for awhile and feel like there should be a duplicate bug, but I can't seem to find one. I feel like many people have themes which aren't actually displaying at all as intended as a result of this.
Thanks for posting the bugreport.
This is actually a very odd bug. I will explain. The values of every option are stored in the theme file and are readed like strings. The python bool function return always true if the input is a string, so bool("False") is true. And that was the problem. The theme says that the pattern_engine needs to be "False" and awn-manager sees True.
I've made a patch, so it will not take long before this issue is solved in the trunk.