Acutally, it is only mouse clicks that are not working anymore. The keyboard is still responsive.
Provide the following system property when starting your application, that you want to debug:
For Eclipse, you can configure your debug configuration as follows:
In the VM arguments: field, paste
-Dsun.awt.disablegrab=true, press on Apply or Debug.
The UI should stay responsive now!
PS: this issue has been already reported here.