VST, Windows 8, FL Studio
When I drag one of FL Studio's windows over my plugin's interface and then drag it back off, it leaves multiple copies of the interface's GUI, stacked up on top of eachother. The sliders, dropboxes, etc aren't movable in these copies so it seems like a graphic glitch. In the attached pic check out the right side of the plugin. That happens when I drag the little window to the right of the plugin over the plugin.
I don't know whether the space to the right of your GUI is part of your plugin's window, or FL's parent window.. If it's FL's window, then it's their bug, but if it's part of your window, then it looks like you're not filling the entire background of your component. Perhaps you're only rendering your GUI controls, when the component is in fact bigger than you think it is?
Originally that space to the right (which is part of the plugin window) wasn't there and the extra guis were filling up the black border around the synth. This was a little tough to see so I extended the right side.
But I just tried adding
g.setColour (Colours::black); g.fillAll();
to the editor's paint() method, and now it's hot happenning anymore. For whatever reason. Thnx.