On Tue, Oct 6, 2015 at 12:12 PM, Reindl Harald <h.reindl@thelounge.net> wrote:
"how do you write a window manager when the graphics system doesn't behave as documented" is pure nonsense given that KDE4 had a working window manager on the same hardware

I agree with you but it's academic at this point.  Plasma5 broke compatibility with certain hardware.  Bug reports exist, but they simply aren't a priority.  I think the message is clear, you can either wait it out or switch to something else.  Rex was right, it is time to move on.  In my case it's to LXQt.