As a long time Fences user, I gave Curtains a whirl.
Make it a bit more apparent that people can create their own themes. After trying a few of the themes I uninstalled the program as I initially felt limited by minor customization to a selection of themes I did not quite care for. I then learned (after coming to the form) that there is a method to create themes from scratch, though it is not made clear in the UI.
