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

ADDITIONAL OS VERSION INFORMATION :
Mac OS X Yosemite 10.10.4.

A DESCRIPTION OF THE PROBLEM :
I create a confirmation dialog using JOptionPane.createDialog. Since upgrading to b27, if I show this dialog to confirm a drag & drop operation, I cannot click on the buttons in the dialog (there is no visible feedback, no response). I can still use the keyboard to select the buttons, however. The problem does not occur when I use the confirmation dialog for any other action, only drag & drop. The problem did not occur with the early access release of 1.8.0_60.

I noticed that when the problem occurs, I can still click on the close button of the application's window. There is no immediate feedback, but if I then use the keyboard to dismiss the confirmation dialog, my application does respond to the click on the close button.

REGRESSION.  Last worked in version 8u60

ADDITIONAL REGRESSION INFORMATION: 
Worked correctly with the EA release, failed after I installed b27.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
I have an extension of TransferHandler. From the importData method, I call a method that creates the dialog using JOptionPane's createDialog method (before importData returns). When showing the resulting dialog, the buttons cannot be clicked.


REPRODUCIBILITY :
This bug can be reproduced always.