VST3 issue in FL studio

on mac (I didn’t test on windows)
the plugin becomes totally buggy (mouse event issue ?) after you open the FL “settings” in the plugin window.

To reproduce:

  • build the AudioPluginDemo vst3

  • instantiate it in FL studio

  • click on the keyboard to play a few notes, drag the knobs. everything is fine.

  • click on the small “gear” at the top of the window (just on the left of the plugin name), that opens a small header at the top (if that switches to a new view, just go back to the plugin view).

  • click on the keyboard -> the notes will stay down

  • try to change a knob value -> it’s buggy

anyone knows if its a known issue, a Juce bug, a FL bug, …?

I’m able to reproduce this. When you open the header menu at the top of the plug-in window we a loop of endless callbacks:

getSize() -> canResize() -> checkSizeConstraint() -> onSize() -> getSize()

This causes the UI to freeze up and the CPU usage to spike. We’re returning the expected values here and none of the sizes are changing so I think it might be an issue in FL Studio. I’ll try to raise it with the devs.

thanks for taking care of that Ed.
Hopefully they will fix that soon, at the moment vst3 are unusable in FL because of that.

Is there any workaround we could do meanwhile to break that endless loop?

Setting the plug-in as non-resizable will fix the issue, I’ll see if there are any temporary workaround for resizable plug-ins.

OK, I’ve been in contact with one of the devs at IL and he’s got a fix that’ll be in the next beta build of FL 20.5.