if you have an app that is still loading and you click on the first app beneath (z) it doesn't bring the app in front

[dinamic]

ubuntu 17.04 unity8

if you have an app that is still loading and you click on the first app beneath (z) it doesn't bring the app in front (see attached screenshot)

so, have some random app (kate) opened
and then in front (z) run something that doesn't load or takes long to load (black window with the loading spinner) i run clementine, seems to not load here on Xmir

now click on the window beneath with the mouse, it doesn't bring the window beneath in front of the loading app (and exception is that if you click on the title bar it does work). it's the same the other way arround