Combobox cause a new connection

Recently, we converted an Access back-end to SQL server and discoverd 
hundreds of connectons per hour for about 25 people using it. Finally, we 
figured out that very combo box with a table query as rowsource created a 
new login every time the form is loaded. We're using windows
authentication, 
so no user/password is required...fortunately!

Is there any way around this?