There is no distinction between the different states applications with breeze-dark with the icons-only task manager.
Here is an annoted comparaison of Breeze (wich works fine) and Breeze Dark (wich does not works) :
http://imgur.com/a/tk4mY 
Using Breeze-Dark there no visual distinction (or glitchy distinction, with ulgly and not predictable semi-transparent textures) between the different states applications wich are:
* Application marked as launcher
* Application Opened, visible, not-focused
* Application Opened, visible, focused
* Application Opened, minimized, not-focused
* Multiple instance of Application Opened


Reproducible: Always

Steps to Reproduce:
1. Change the Desktop Theme to Breeze Dark
2. See the icons-only task manager
3.

Actual Results:  
No distinction between the different states applications with breeze-dark with the icons-only task manager

Expected Results:  
Breeze Dark must use same visual pattern as Breeze.

Archlinux.

breeze 5.4.3-2
breeze-icons 5.16.0-2

plasma-desktop 5.4.3-1
plasma-framework 5.16.0-2
plasma-pa 5.4.3-1
plasma-workspace 5.4.3-1

kde-cli-tools 5.4.3-1
kde-gtk-config 5.4.3-1
kde-templates 15.08.3-1
kdebase-runtime 15.08.3-1
kdeclarative 5.16.0-1
kdeconnect-git r1098.f925345-1
kdecoration 5.4.3-1
kded 5.16.0-1
kdegraphics-okular 15.08.3-2
kdelibs 4.14.14-2
kdelibs4support 5.16.0-1
kdesignerplugin 5.16.0-1
kdesu 5.16.0-1
kdewebkit 5.16.0-1
polkit-kde-agent 5.4.3-1

libdbusmenu-qt4 0.9.3+15.10.20150604-1
libdbusmenu-qt5 0.9.3+15.10.20150604-1
modemmanager-qt 5.16.0-1
polkit-qt4 0.112.0-1
polkit-qt5 0.112.0-1
poppler-qt4 0.37.0-1
poppler-qt5 0.37.0-1
qca-qt4 2.1.1-1
qca-qt5 2.1.1-1
qt4 4.8.7-3
qt5-base 5.5.1-3
qt5-declarative 5.5.1-3
qt5-graphicaleffects 5.5.1-3
qt5-location 5.5.1-3
qt5-multimedia 5.5.1-3
qt5-quickcontrols 5.5.1-3
qt5-script 5.5.1-3
qt5-sensors 5.5.1-3
qt5-svg 5.5.1-3
qt5-tools 5.5.1-3
qt5-translations 5.5.1-3
qt5-webchannel 5.5.1-3
qt5-webkit 5.5.1-3
qt5-x11extras 5.5.1-3
qt5-xmlpatterns 5.5.1-3
qtchooser 53-1
qtwebkit 2.3.4-2