Window decoration bug on Yosemite?

[Chris Newland]

Hi,

I think there might be a bug with the window decoration on OSX Yosemite
whenever the StageStyle is set to UTILITY:

initStyle(StageStyle.UTILITY);

The red close icon appears twice. Once on the left as expected but again
in the right most position where the green maximise icon should be.

Screenshot here: https://github.com/AdoptOpenJDK/jitwatch/issues/135

Bug occurs in:

Oracle 1.7.0_72
Oracle 1.8.0_25
Oracle 1.8.0_40ea
OpenJDK 1.9.0

I've had a look around in the OpenJFX source but haven't been able to
track down the cause yet.

Kind regards,

Chris
@chriswhocodes