Using new iMac 27 inch with Retina display and Acer S271HL 27" LED Monitor - FullHD at 1080p Since the last update (not 54.0 but the one previous). The drop down box of U.S. States is incomplete on multiple sites stops at South Carolina). This is happening only on my second monitor. I can unequivocally confirm that it worked fine before that Firefox update. If I drag the browser window over to my Retina display, then all of the states appear normally. Drag it back to the 2nd monitor and the list only goes to South Carolina again. (It also displays only a partial list of shipping options on the sites I use that have them, again when moved to main screen, it's fine). I have tried changing the second screes resolution, and have been thru all of the other changeable parameters that the second monitor has with no luck. I brought all of the same sites up in CHROME and they all work fine on the second monitor. All of the drop down boxes show all of the intended selections. Process of elimination shows it has to be a Firefox issue.