Receiving field has no value error when it does

[super_spazz]

I am trying to populate a field with data from two other fields on the same
form. All data is manually entered, no db lookup.

So, here is what I am trying to do:

AllSameForm

Field1 contains "this"
Field2 contains "that"

I want Field3 to auto populate with the value "this-that"

Field1 is manually entered
Field2 is manually entered
Field3 I want values of field1 and field2 concatenated with a dash in
between the two values. My code for Field3 in the Control Source box is
=[Field1] & "-" & [Field3].

The field *does* populate with the correct output. The problem is, when I
am finished and want to close the form, it complains that Field3 needs to
contain a value. I am confused because it auto-populated and I can see it
with my eyes. Not sure why Access believes there is no data in this field
when there.

Any help is greatly appreciated. Thank you.

Jessica

 

[super_spazz]

Correction:

I had a typo. Code for Field3 is this:
=[Field1] & "-" & [Field2]