Tri-state checkboxes

[Mark Powell]

Ken:

Sounds promising.  Is the size/location of the underlying checkbox
predictable enough for this?  i.e. it doesn't pixel-creep from platform
to platform?  

Mark


Well, the closest you can get is to have a single image that shows the
equivocal state that is put on top of a real checkbox, and is hidden. 
When the user clicks on the checkbox, you check the current state of the
hilite and if it is true (checked), you show the equivocal image on top
and allow the mouseup to continue (which will change the checkbox to
cleared (unchecked), but beneath the equivocal image. Then when the user
clicks on the image, you have script that simply hides the image.

Then to find out the "state" of the checkbox, you'd just check the
visible of the image - if it's showing, you're in an equivocal state; if
not, you take the hilite of the checkbox.