#548 Layout Editor on iMac loses keyboard

[johnwmcc]

After I've been using Layout Editor for anywhere from a few minutes to perhaps as long as half an hour, I suddenly lose keyboard input to the program, and indeed to ALL programs on the computer.

Restarting JMRI and disconnecting/reconnecting the Apple Magic Keyboard (Bluetooth), and even plugging in the keyboard lightning cable, don't restore keyboard function. The only fix I have found is restarting the computer.

I have an iMac 27in 5K retina machine running El Capitan v10.11.3. JMRI version 4.2.1-R6b484b4. Java version 1.8.0_73 (en_US) - all recently downloaded/updated.

Anyone else had this problem? I couldn't find anything relevant in this bug list searching for 'keyboard', and only three hits of any kind for 'keyboard'.