hello, i suppose when you test alpha software on an alpha operating system there are bound to be problems... in order to rule out an issue with hardware acceleration, please try launching the app in firefox safemode once: Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

otherwise you might want to report that issue at bugzilla.mozilla.org, but make sure to include your information from about:support

well surprisingly safe mode should works. I didn't even think of that.... i.m going back to normal mode and find which add-on cause it....

And if you have e10s enabled in recent Nightly (look in Options->General) then you are working with three different things in Testing.

Did not find any mentions for Windows 10 and options while skimming the recent Nightly Builds threads in http://forums.mozillazine.org/viewforum.php?f=23 nor mentions of conflicts of e10s and Win10 in Multiprocess Firefox [e10s] thread.

Also the Nightly update on Monday (as there are checkins usually everyday so therefore a update that day) should have your useragent showing NT 6.4 instead of NT 6.3

Thanks. It's solved by turning off gpu rendering, no addons participating. It's intel HD 3000 and nvidia 710m...well windows tell me it's hd3000&710m So need I submit it to bugzilla now? unable to upload the screenshot...

so i guess the hardware vendors have not released drivers for the new OS yet, which is probably not the domain of mozilla. if it works correctly with hardware acceleration disabled, then i'd leave with that for the moment...