User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:54.0) Gecko/20100101 Firefox/54.0 Build ID: 20170612122310 Steps to reproduce: Update Firefox (linux) from version 52 to version 54. Flash version 26.0 (remains untouched before and after upgrade) Actual results: After upgrading Firefox (linux) to version 54 introduces serious lag when Playing Settlers Online (Web/Flash based game). Lag seems to happen when the mouse is clicked. Expected results: No lag during game play as with previous version of Firefox.
Have trued Ubuntu, fedora, Suse linux, all have the same issues. All installations "upto date"
Created attachment 8886836 [details] Screenshot from 2017-07-16 09-01-39.png Attached screenshot showing plugins
The probable cause of this is that we forced all Flash elements into windowless mode on Linux. This is a tradeoff we made to support multi-process browsing, and makes the browser faster in general but causes painting slowness for large Flash elements/games. Given the declining state of Flash, Mozilla isn't going to dedicate a lot of engineering resources to this (P5). I'll leave this open in case somebody comes along and wants to do profiling and identify a problem we can fix.
Is there a way to re-enable flash into windowed mode?
No. The code that supports windowed mode has been completely removed.