Users can restore UAC's interruption to Firefox updates if they wish by clearing a box in the "Advanced" section of the Options window.

Mozilla has just one more component on its silent update to-do list.

That piece, now scheduled to appear in either Firefox 13, which ships June 5, or Firefox 14, slated to release July 17, will apply the update entirely in the background so that the user no longer sees an update installation progress bar.

Called "background updating" by Mozilla, the process will seem invisible to users because the update is automatically applied, then staged in a different directory or folder than the current copy of the browser. The next time Firefox is launched, the staged directory swaps places with the active directory.

Mozilla has been chasing Google's Chrome, which has featured silent, behind-the-scenes updating, since the latter's 2008 debut.