Call to Undefined Method when searching after copying form and changing table

HELP! Receive “Fatal Error: Call to undefined Method…lookup…”. This occurs attempting to perform 'quick search" on forms that were copied and the root tables were changed. The error indicates the form is still trying to search using procedures/field names from the original table.

For future reference: I have run into this error when I have to make a change to the underlying table structure after a Grid has been built.
For example I had a field that was TinyInt that I had to change to Int.
After that… I received the Undefined Method error.
To get rid of it I somehow go the Grid to rebuild itself by selecting different Grid Orientations Under Grid Modules.
Hope this saves someone from rebuilding their Application.