[Update] 2016-04-26

Manjaro 15.12 update-pack 17:

Included in this update:
Firefox-kde 45.0.2
Plasma 5.6.3
KDE framework 5.21.0
KDE Applications 16.04
qt4 4.8.7-8
qt5 5.6.0-4
Samba 4.4.2
Thunderbird-kde 45.0
Virtualbox 5.0.18
Vlc 2.2.2-4

Current supported kernels:
Linux310 3.10.101
Linux312 3.12.58
Linux313 [EOL]
Linux314 3.14.66
Linux316 [EOL]
Linux318 3.18.32
Linux41 4.1.23
Linux44 4.4.8
Linux45 4.5.2
Linux46 4.6-rc4

This update also includes the usual Archlinux upstream fixes as of Apr. 26, 2016.

You can use Discover, Octopi or the command line for this update:

sudo pacman -Syu

Official Manjaro Announcement: https://manjaro.github.io/Update-2016-04-26_(stable)/
Official Manjaro forum thread: https://forum.manjaro.org/index.php?topic=33377.0

Mostly ok, but the update to GTK 3.20 (as detailed in the Manjaro forum post) seems to break the Breeze-gtk theme, so everything looks weird in Firefox, and it doesn’t use the system cursor theme.

There has been a cursor theme setting added to Plasma’s Gnome Application Style (GTK) settings.
However yes, GTK 3.20 does indeed break GTK 3 themeing once again. This is an upstream issue that the Plasma artwork team will need to fix.

I too have experienced problems with the breeze-dark theme not being honoured in Firefox. Selections were not visible and text typed in text boxes was not of sufficient contrast to be intelligible.

While this is being fixed upstream, I saw this workaround at the Arch Linux Reddit. Both selections and typed text are now visible.