During a recent build, we ran into an issue that left us scratching our heads. IE refused to load the main stylesheet. Normally, something like this would be caused by a faulty configuration file, but seeing how all other browsers worked fine, it came down to IE being IE.
As it turns out, IE has an undocumented limit of 32 individual stylesheets. Now, this isn't a huge concern for production sites since we compress all stylesheets to keep the load time to the minimum. It is however a problem in a development environment, where IE debugging needs to take place.
This is where IE Unlimited CSS Loader steps in. It will use the @import method to load an infinite amount of CSS files allowing for smooth theme debugging. There are some concerns with using this module in production sites, as there is a potential performance hit and possible conflicts with other modules, but it is a lifesaver in a development environment. Once development is done, simply turn off the module and those concerns go out the window.