I have written a plugin which allows the user to view multi-page TIFF images within firefox. The problem is that Quicktime also thinks it can view TIFF images. How does Firefox chose which one gets used?

through trial and error I've determined that:

• Sometimes, my plugin (Accel VIewTIFF) just runs, and everyone is happy.
• Sometimes I need to disable Quicktime in the Add-ons window.
• Sometimes I need to remove the QuickTime plugin files from the / Library/Internet Plug-ins folder (I'm on a mac)
• Sometimes I can put QuickTime BACK after having successfully run Accel ViewTIFF.

I've yet to figure out when (if ever) each step is necessary.

Please help me escape the cargo cult! (or at least point me to the right place in a manual.)

thanks.