Hello,
I know not many people use my themedev.module, but it has a few fans. So I'm here to announce it's now compatible with 4.7 and has gained a block.
The block has a compact version of the settings page, allowing you turn flip the various stylesheets on and off more easily. It's also set to position fixed so it floats above the content of the page, and can me moved temporarily by double clicking on the title of the block.
I've also separated the form highlighting styles to a different stylesheet - though this isn't that helpful because not even Firefox/Safari show much generated content on form elements. (Opera does better but crashes on my mac...)
For those of you who have never used Themedev it simply uses diagnostic styles to highlight page structure - those of you with well established patterns of working with bookmarklets/wed developer toolbar and such like will probably find little to interest you in Themedev.
One problem with those however is persistence - every time you surf to a new page you lose the highlighting. The latest version of the web developer toolbar allows you to 'persist styles' which helps, but it's clunky.
I actually spent a couple of hours looking into moving themedev functionality to a Firefox extension, but decided against it for now. However with continued improvement of the Firefox extensions[1] available I'm thinking this will be the last time I update Themedev. Either better tools will become available or I'll be moving it's functionality to Firefox myself :)
[1] Some of the Firefox extensions I like for development work:
DOM Inspector http://www.mozilla.org/projects/inspector/
Web Developer Toolbar http://chrispederick.com/work/webdeveloper/
Firebug http://www.joehewitt.com/software/firebug/
CSSViewer https://addons.mozilla.org/extensions/moreinfo.php?id=2104&application=f...
View Rendered Source Chart http://jennifermadden.com/scripts/ViewRenderedSource.html
Aardvark http://karmatics.com/aardvark/
X-Ray http://www.designmeme.com/xray/