Prevent node editor from closing when expression entered but not checked
Merge branch 'master' into joinerr
Working on stopping close with unentered equation.
Code review:  Doesn't work in author mode.
Workaround for equation checking before node editor closing in author mode
Code review for unentered equation on node editor close.
Merge branch 'master' into haoxuan3
Skeleton for getting state into the PM.