#38 Invalid entry field pairs can trigger infinite loop

[Andrew Barnham]

Consider simple window with two entry controls. Both exactly same thus:

a long(-1)
entry(@n3),use(a)
b long(-1)
entry(@n3),use(b)

If you change focus between them both while they both contain invalid values then the system will infinite loop as both entry controls compete to acquire focus

[Andrew Barnham]

Bugfix checked in