I found a weird GUI problem when I was debugging my plugin in the EnergyXT host (v2.7) on Mac OS X Yosemite 10.10.3. It also happens with the Juce Demo Plugin built from the current JUCE git tip. Whenever I close a plugin GUI window, I get a stuck borderless dark grey window on screen that will stay there until I close energyXT. The rectangle has the size of the plugin client area. When I open multiple GUIs and close one, all other instances close as well. It seems something is off with how windows get added or removed from the desktop with this host.
Has anyone else seen this issue? Is there a workaround? Other plugins made without JUCE are not affected by the issue.