Changed text box to combobox for Manufacturer on main form (Another example of how combobox dropdowns work)
Changed Recordsources of both main and subform to a single table instead of joined tables (resolved problem of attempt to successfully update multiple tables via one form).
Fixed combobox functionality on subform for Vendor.
Removed table lookup fields in table design.
Added simple form for updating vendor table. You call the form by clicking the icon at the bottom of the vendor combobox dropdown.
The blank form at startup is because the form is looking at parts in tblMstrParts that have null PartNumber. Those records need to have a partnumber added.
Also there are a large number of records in VNDPRT with blank VendorID. Those also need to be fixed.
The blanks were probably introduced during your testing changes.
Looking good. Any problems post back.
Edit: Deleted and replaced attachment v01 with v02. For some reason the search combobox macro quit working with an error. I converted the macro to VBA and it worked OK.