I am using the direct download of Firefox and in V46 there is a bug (see their bugzilla #1234158) where using GTK3 3.20 it does not correctly show radio buttons or the scrollbars (scrollbars work but you cannot see the slider so you have to guess). I am reporting this here for the benefit of other susers who may use the direct download of Firefox. Not sure yet when the fix for this problem will be rolled out. There is also apparently a problem with the mouse cursor selection in FF.
Stuart
I’d like to note that openSUSE’s Firefox package is still using GTK2, so is not affected.
There is an experimental build with GTK3 available, but you’d have to explicitly install that from a separate repo.
I found that Tumbleweed has now got Firefox 46 in the official repo and so I tested it. The issue with scroll bars seems to be fixed so I can only assume they added the patches before releasing it, I have not checked out the issue with Radio buttons not showing but will when I get a chance. The Firefox releases available as direct download so far still exhibit these problems (at least with the d/l from Sunday 8th May that I tested).
Stuart
No, we didn’t add any patch.
As I wrote in my previous reply, openSUSE’s Firefox packages still use GTK2, and are therefore not affected by this problem.
The Firefox releases available as direct download so far still exhibit these problems (at least with the d/l from Sunday 8th May that I tested).
They probably use GTK3.
I thought the whole point of release 46 was GTK3…
Stuart
Upstream, yes (I think). Though not the whole point of release 46 is about GTK3 either… 
In openSUSE we haven’t switched yet, due to (possible) problems.
You can track the (openSUSE) state here:
https://bugzilla.opensuse.org/show_bug.cgi?id=977710
PS: see also http://lists.opensuse.org/opensuse-factory/2016-04/msg00293.html
Ah OK understand FF 46 is compiled with GTK2 at present for openSUSE. I’ll keep an eye on both your info you suggested and keep looking for a new download from Mozilla to see if their fixes work.
Stuart
I tried Mozilla’s build of Firefox 46 on LEAP and except a cursor issue I didn’t notice any difference
the cursor turned black inside Firefox as if it was running on a different display server.
I thought that Mozilla’s build was supposed to be statically linked to support a larger base of Linux distributions, linking to gtk3 seams like a bad idea.
This should be reported to mozilla
Yes I had noticed the cursor issue as well, for some reason FF does not always honour the system choice for cursor. This has happened to me in the past on some versions, annoying but not as bad as the issue with things like scroll bars and radio buttons which directly affects usage.
Stuart