For convenience I am giving the sub dash a name - "Display Dash". Well... I think -
- In case of one window, you do not need this Display Dash.
- In case of two windows, just display the names just like current one. In the list there will be only 2 names. Instead of starting the list from the top, you can start it from the center of the left side. (like this
http://img853.imageshack.us/img853/8283/screenshotm.png)
- In case of 10 windows, just put a scrollbar in the right side to the list, so that all windows can be scrolled.
The design is very good. I think the website address can be removed from the list, only favicon and site page title is better. Also can you please try with a thinner border for the Display Dash. I think the thinner border will make it better.