Unusual behavior?

Listbox1 in the double click event feeds listbox2 with an add item.
Which is fine. The listbox1 uses files as its type.
Occasionally the user errors and selects a [..] file.
Okie we dont like or want this so we have a double click event in listbox2 that does a removeitem, which works fine.

However when the following occurs:
Action Listbox1 listbox2
Click Listbox1 [..] -> [..]
click Listbox1 filename.txt -> filename.txt
DBlClick Listbox2 gone [..]
Click process button
.displayvalue of listbox2 is null instead fo filename.txt

in essence with a removal of the firstitem in the listbox2
the filename.txt moves to the top but its values are now null instead of what is the next item in the list.

Any ideas how to get around this?
we have tried
.refresh
.selectedid(1)

Thanks