PopupMenu stealing focus

VST, Windows 8, FL Studio 11

When I click a ComboBox in my synth plugin and then close the PopupMenu,  I can no longer play the synth with the QWERTY keyboard. I have to click anywhere in FL Studio to get QWERTY function back.

I was having the same problem when clicking anywhere on the synth, but fixed that by calling setMouseClickGrabsKeyboardFocus(false) on every component in my plugin. But I can't do that with the combo box's PopupMenu. Any ideas?

Is there a way to prevent any part of the plugin from grabbing keyboard focus? I tried toggling the "Plugin Editor Requires Keyboard Focus" in Introjucer but that didn't make a difference.