Now it worked, thanks!
What version of Qt did you install ?
What graphics card are you using ?
Did you check whether you had up to date drivers ?
Well its the first time I ever saw anyone ask for it so unless you open report and vote for it,
it's unlikely it will change in newer versions.
Also, it should possible to grab from code but it will fiddle with internal
objects and might break anyway on next upgrade so maybe just taking the lines
is the best solution.
@jsulm It has no business with g++. g++ is installed, and even though not, I have clang++ still.