FYI - bug?
AU-Host Plugin Windows and setUsingNativeTitleBar(true)
i modified my plugin-host (based on the Juce Plugin-Host), to juse native window borders via setUsingNativeTitleBar(true) in the PluginWindow-Class (from the Juce-Plugin Host example)
In this case, all newer juce-plugins (not the older ones), will not appear (you only see a empty window)