User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:51.0) Gecko/20100101 Firefox/51.0 Build ID: 20170125094131 Steps to reproduce: Updated Firefox to version 51.0.1. I have Windows 10, 64 bit, customized Windows display "Change the size of text, apps, and other times:" to other than 100%. Actual results: SWF items "tearing", not displaying properly. See attached screenshot. Expected results: SWF should work properly. There was no problem before version 51. Disabling hardware acceleration in Flash and Firefox solves the problem for some SWF objects, but not all. Speedtest.net is one that is always affected.