Windows Explorer forces file type search

[DavidOS]

Hi,
When I launch Explorer and do a file search, the files are correctly located. Therefater, the file type drop-down is populated with the first option in the drop down list (happens to be 3GPP). I cannot disable this entry so Explorer narrows it's search to 3GPP files. I have tried every combination of search settings with no results.
To do a second search, I have to relaunch Explorer.
Anyone seen this?
Thanks

[techniner]

So if you just did *.3gpp in the initial search, what happens?

Also would it be possible to take a snap shot so we can see exactly what your seeing?

[DavidOS]

Searching for *.3GPP returns nothing.
No matter what the initial search is for, Explorer stuffs the value 3GPP into File Type and I can't delete it (except by closing and reopening Explorer)