I have a following table:

CREATE TABLE document ( doctype C(1), id N(7), .... )
INDEX ON doctype TAG doctype

This table contains 200000 records and sometimes only some of them are of
doctype=='A' .

BROWSE FOR doktype='A' works fast. I want to edit this table in a grid. I issue the command

SELECT document
SET ORDER TO
SET FILTER TO doctype='A'

in load event of a form.

When this form runs, the grid will appear extremely slowly. It seems that
FoxPro will not use index in grid refresh: it scans the whole table. Also,
when user presses up/down arrow in first/last row, this scanning begins again.
Therefore, FoxPro cannot be used for data editing in a table.
Maybe this can be resolved using local views, but this requires using a database, but my table is for compatibility reasons free table?
Maybe the following trick helps: adding a dummy non-visible master grid to form and making dummy parent-child relationship. However, child grid order cannot be controlled if this is used?