checkbox triple state

[Stanley]

I have a bound checkbox and I set its triple state property to true. I can't
update the checkbox. If it is unbound I can cycle through true, false and
null.
What am I missing.
Thanks,
Stanley

 

[Douglas J. Steele]

You're not missing anything.

Boolean fields can only be True or False, so when a checkbox is bound to a
boolean field, you lose the ability to have triple state.