What would be an effective and efficient way to branch code execution in the following scenario;

Textbox1 on form1

Lookup for possible values for textbox1 on form2

If textbox1 is empty, abandon new record, *unless* form2 has gotten focus, ie: user wishes to lookup value for form1.textbox1 using form2.

I already have the code for EMPTY(this.value) on form1.textbox1.lostfocus. Where could I test for form2.gotfocus()?

Thanks in advance for any pointers.

Andrew