since upgrading to Mac 10.14 (Mojave)
Workbench exits many times in different situations:
deleting text, compiling, starting debugging, cut out text.
I used the latest installer of Workbench, not the beta version:
Version: Neon.3 Release (4.6.3)
Build id: 20170314-1500
JRE is: Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
I recommend others not to upgrade to Mojave.