Rated 5 out of 5 stars

This is absolutely the best look I've been able to give TB in a long time! Nice work!

This review is for a previous version of the add-on (1.0.1). 

Thanks.

Excellent!! Rated 5 out of 5 stars

This does exactly what you say. Absolutely beautiful! I've been wanting the glass effect applied to more of the TB -- and FX (I use the FX version, too) -- UI than was available previously, at least without having to learn CSS and whatever else I would have to learn to make that happen. Two questions: (1) Can you add options to alter the transparency of the viewing pane, too? (2) Have you thought about developing an extension for Lightning to accomplish the same thing you do in TB?

I've noticed three slight issues, though:

1. I'm using Compact Menu 2 with both TB 9.0.1 and TB 10b5 (both running on Vista w/ latest SP and KB fixes installed) and noticed a big difference in the way the drop-down main menu renders in the two versions of TB. In TB 10b5, it's almost fully transparent and the main menu is difficult to read because it overlays part of the folder pane and the folder names are very visible through the "glass-ized" background of the main menu; it appears the glass effect renders differently between the two versions of TB.

2. In TB 10b5, when I move my cursor up and down the drop-down menu listings for the main menu (File, Edit, View, etc.), each main menu entry is highlighted but the highlight remains when the cursor moves off one entry and onto the next. The net effect is the drop-down main menu turns dark because the highlights remain and are not removed when the cursor moves off an entry. This behavior does not occur on any of the secondary drop-down menus, though.

3. I'm not entirely sure and will need to double-check, but I think the configuration options the extension presents in its interface differ between the two versions of TB.

None of these issues is anywhere near a deal-breaker, though.

Let me know if you want me to send you screenshots and where I need to send them. Keep up the great work, though. I really enjoy the results of your work. I wish I had some of the same talents; I can only appreciate others' talents.
~~~~~~ EDIT 2012 Jan 26 ~~~~~~
Thank you for your quick response, Aris. This is the first time I've been back to this review to check for a reply. I run Vista only on one machine, my laptop, but haven't had it up since I wrote my original review. My other machine is a desktop still running XP. Anyway, I'll get you the screenshots you requested in a couple of days -- and install the dev version you mentioned. I'm looking forward to seeing what it does with Lightning.

This review is for a previous version of the add-on (1.0.1). 

First of all, thanks. ;-)

q(1): transparency is handeled by Windows. Do you have a special pane in mind with "viewing pane"? -> Screenshot?
q(2): Lightning support will be added on next release. http://imageshack.us/photo/my-images/341/74885820.png/

issues:
1: thats strange, I do not see any difference between TB9.0.1 and TB10b4 in behavior of drop down menus even not compact menu 2. -> Screenshots. If the text is unreadable somewhere, you can try another dropdown menu text setting.
2: You meant TB10b4, I guess, b5 isn't out yet ;-) -> Screenshots please, no such problems here.
3: Maybe you have GMB 1.0 and 1.0.1 installed on dif. machines? There was a small textstring change, nothing more.

You can send screenshots to my mail adress aris-t"at"gmx"dot"de or post links to screenshot here into comments area. I will setup a support forum later.

*****************************
EDIT:

I've added a dev version with Lighning suppport. Check versionspage:
https://addons.mozilla.org/addon/glassmybird/versions/