Created attachment 128754 [details]
hwinfo

System: openSuse Leap 42.2,
kernel from download.opensuse.org/repositories/Kernel:/stable/standard/
4.9.0-4.g1af4b0f
Mesa from download.opensuse.org/repositories/X11:/XOrg/openSUSE_Leap_42.2/

graphics adapter: amd radeon rx 460
cpu: i5-6402p

desktop: kde5 (from 42.2-oss/update)

Problem: Address-drop-down in firefox flickers.

Steps to reproduce:

start firefox
enter address (example: www.heise.de)
enter an other address
address drop down starts to flicker.

Perhaps problem shows up only when virtual desktop has been changed before
firefox was started. (I use cube animation for virtual desktop change.)

Problem also occurs with tumbleweed live system.

There is no problem with kernel 4.8.x (4.8.14)

I've also reported this bug at
https://bugzilla.suse.com/show_bug.cgi?id=1017938