When working with 4D v11 SQL array based List Boxes you should aviod direct manipulation of the size of installed arrays. Instead use INSERT LISTBOX ROW and DELETE LISTBOX ROW. This facilitates the proper maintenance of the internal references maintained by the 4D.

When using array based List Boxes, the List Box object itself is defined as a BOOLEAN ARRAY. When using the List Box command to insert and delete rows 4D keeps the size of this boolean array in sync with the size of installed arrays. If the user calls DELETE FROM ARRAY on installed arrays the internally managed List Box arrays can become critically out of sync and cause unpredictable negative side effects.