Highlight current field when have multi sub forms

I have multiple (Continuous Forms) sub forms on one main form

I'm using on got focus = clolorYellow([myfield])
on lost focus = clolorWhite([myfield])

Then public function clolorYellow(fieldname as control)
Fieldname. backColor = 65535
End function

2 issues
One, this function select that column (not just that record.)
Two, when I go to the second sub form, the first form field stays highlighted, I guess the on lost focus doesn't work because that field also has the focus.
Any help?
Thanks