Setting the sub form to display blank when driven by a lookup combobox

[Joe]

Hi All

I have a main form that uses a lookup combo box and then a sub form
that displays the associated Child record based on the selected lookup
value. When first opening the form I have set the code to make the
lookup display a value of blank. However, my sub form still displays
the first record in the associated table. Is there anyway to make the
subform display no record upon opening the form for the first time?

Thanks in advance!