Mozilla Suite : Issues : Themes
From MozillaZine Knowledge Base
Why won't Firefox themes work in the Mozilla Suite?
The Mozilla Suite and Mozilla Firefox programs, though similar, use different theme formats. Both programs have many themes developed for them, and some themes are only compatible with a specific version of Mozilla Suite or Firefox. If you'd like to view a list of themes for Mozilla Suite, visit the themes page at Mozdev.org or Mozilla Update
I upgraded Mozilla Suite, and now the theme I use doesn't look right or causes other problems.
Only the Classic and Modern themes are automatically updated when you install a newer version of Mozilla Suite. Occasionally, Mozilla Suite development introduces incompatibilities with other added themes that were designed for older versions of the program. If you attempt to use a theme designed for an older version of Mozilla Suite, problems such as visual artifacts, oversized toolbars, browser instability and startup failure can occur. To avoid these problems, only install themes that are designed for your specific version of the Mozilla Suite. To uninstall older, incompatible themes, open the Edit menu (Mozilla menu on Mac OS X), choose "Preferences -> Appearance -> Themes", select the theme you want to remove and click the "Uninstall Theme" button.
The new extension I installed shows Modern icons in my Classic theme.
A few extensions (notably Calendar) seem to do this on first installation, but the solution is simple: change your theme to Modern and then back to Classic. If the extension has classic image icons at all, they should be picked up as intended.
I keep getting random corruption of button images and Mozilla Suite is unstable doing certain things.
A general first step solution to theme corruption is to delete the XUL fastload file, which precompiles and stores the user interface files for quicker startup. Exit Mozilla Suite completely (including Quick Launch if enabled), open your Mozilla Suite profile folder and delete the file "xul.mfl" (Windows) "xul.mfasl" (Linux), or "XUL FastLoad File" (Mac OS X). The file will be regenerated when you restart Mozilla Suite. If the problem persists, see this article for additional suggestions.