FULL PRODUCT VERSION :
java version "1.8.0_60"
Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
JavaHotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.3.9600]

A DESCRIPTION OF THE PROBLEM :
It seems that the iconifiedProperty in the Stage class is bugged when the stage is UNDECORATED. When I added a listener to the property the results were weird. If the stage is undecorated, the window should not hide or restore when the taskbar icon is clicked. This seems to only apply when the stage is not iconified. But if I call setIconified(true) and then click the taskbar icon, it will restore the window and call the event. But this doesn't happen when the stage is not iconified and the taskbar icon is clicked.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1) Create an undecorated stage.
2) Create a button or some control that calls setIconified(true).
3) Add an event listener for the iconifiedProperty.
4) Click on the taskbar icon. The window will not hide and the event will not be called.
5) Click on that control to manually set the window to iconified. The event will be called.
6) Click on the taskbar icon. The window will restore and the event will be called. This should not happen.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
I expected the taskbar icon to neither hide or restore the window since the stage is undecorated.
ACTUAL -
The window restores when it is iconified and the taskbar icon is clicked.

REPRODUCIBILITY :
This bug can be reproduced always.