Since my upgrade to Kubuntu 17.04, with Plasma 5.9.4, I've noticed a few small bugs. One of these is an issue with shading windows -- when they are shaded, the titlebar text completely disappears.

Interestingly, this problem doesn't seem to occur with the Breeze window decoration. With others, such as the Plastik decoration that I'm using, it happens. I've never seen this before, but I thought I'd mention it and see if anyone else has noticed it... Not real sure how to fix it though.