Dialog invisible~

[Esion-lin]

In the ubuntu 18.04, I compile and run project. The problem is that whenever the QFileDialog is displayed for any reason (open/save wallete file(s)) , it remains invisable. And I can close the invisable dialog with Escape. But before connected to bytecoind(setup new ui view), it works well. I tried it on another computer(ubuntu 16) and it has the same problem.