For some reason the EventHandler attached to a Button is not called as soon as Caps Lock is ON on Mac.
It works fine on Windows.

Download the Scene Builder M4 b07 at http://athudson.us.oracle.com:8080/hudson/job/SceneBuilder-promote/26/
Once unzipped load in NetBeans samples/IssueTracking then run it.
In left hand side part select any of the projects then click on "New Issue" in top toolbar: a new row is added to the table, you can edit issue's details in the bottom part.
Fine.
Now set Caps Lock ON and click again "New Issue": the Button doesn't receive the click, it doesn't blink.
This is annoying as one can have Caps Lock ON unintentionally, and from there's nothing to help you guessing what's going on.