tab order skipping some fields

[Guest]

I have set up a form containing two subforms - form view for the main form
and datasheet view for the subforms. Each subform has two controls, the
first of which is a combo box and the second a text box. I want the tab
order to cycle through the controls on the main form, then the controls on
the first subform, then the controls on the second subform, then back to the
main form. I have set the tab order, and the first time I tab through after
opening the form it works perfectly. However, as soon as I move to another
record in the main form, the tab order skips the first field in each subform
(the combo box) and goes straight to the second (the text box). If I close
the main form and reopen it the tab order works properly again for the first
record, but goes haywire again as soon as I change records.

Obviously I've done something wrong, but what?

 

[Guest]

An added twist! I have now put a third control on one of my subforms,
another text box. Now, the first time I tab through after opening the main
form the tab moves to the first control on the subform; the second time it
goes to the second control, and the third and subsequent times it goes to the
third control.

Something somewhere is incrementing, but I can't find what or where!