I downloaded the 30 day free trial of curtains.  I've been playing around with it, and have loaded several of the different included styles.  I've also tried modifying some and making my own from scratch.  I've noticed several things in some of the included styles, that I'm unable to modify in an existing style or when making my own from scratch.  I've been through all the settings including the advanced settings and see no way to change these things.  If I buy the software, will these capabilities be added?  Here are some of the things I noticed, that I was unable to find a way to change:

1. custom start button

2. Custom explorer buttons (minimize, maximize, restore, close)

3. transparency of the title bar of an explorer window

4. "highlighted" color of selected items

5. how a taskbar shortcut is visualized for a program that is opened. 

6. The ability to add the "force glass explorer background" option to a style you create.