Strange display issue, native VST

Hi,

Native VSTs including tunefish4 are appearing strangely for me in qtractor. The UI window appears as normal, with title bar etc, but the actual interface is shown outside it, anchored to the top left of the screen. The controls seem to work ok, the sound is fine, but as the UI is outside the window, it can't be moved, minimized etc.

Any ideas?

V0.9.9 compiled against mint 19. I've read the readme.vst but the header files mentioned are named differently in the 2.4 sdk I downloaded.

Thanks...