Checkbox issue with three state.

I'm emulating the functionality of the old SQL 2000 object search utility.
It has a group of checkboxes for object state, and an override for all
objects.



Now when my All Objects checkbox is checked, I set Checked on all the
'child; checkboxes, and vice versa.  If any child checkbox is then
unchecked, I set the All Objects checkbox to ThreeState and make it
Indeterminate.  Now comes my problem, when that child box is checked again,
I check if all children are checked, and if so try to make set the All
Objects checkbox to Checked.  The Checked property returns true, but the
display still shows Indeterminate.  I even refresh on the control, to no
avail.