The fix for this on production sites is to simply enable the “Optimize CSS files” option on admin/settings/performance. Unfortunately, that option makes developing CSS for themes or modules a true PITA. This module adds a developer-friendly solution to the “Optimize CSS files” feature; it aggregates all stylesheets except for those in the theme or in the selected module.
Private Download Method
Note that Drupal’s CSS optimization (and this module) doesn’t work when files are transferred using Drupal 6’s private download method. See #572516: make private download method support css/js aggregation, color module and js translations This incompatibility is fixed in Drupal 7.
Drupal 7 version
At this time, it appears this module is not needed for Drupal 7. See #228818: IE: Stylesheets ignored after 31 link/style tags
Comparison with IE Unlimited CSS Loader
IE Unlimited CSS Loader:
- has lots of bugs such as this critical bug: #693180: Overriding module CSS files does not work with unlimited_css
IE CSS Optimizer:
- Optimizes all CSS files except for the module or theme being actively developed.
- To prevent a theme's numerous stylesheets from hitting IE's 31 stylesheet limit (common with RTL websites), the 31st and later stylesheets will be loaded with @import statements.