Sub-form Update on Change to Main Form

Hi,

I have created a sub-form and a form, based on 2 tables:

tblCompanies
tblAccount Codes

All is working fine, except for one particular situation. The Primary Key for tblCompanies is a 3-letter code which the user can assign. If the user changes the code in the main form, the records displayed in the sub-form disappear. If you then advance to the next record on the main form and then return to the original record, the updated code is displayed with the appropriate data in the sub-form.

It seems that the cascade update is working fine, it just doesn't update until the record is saved. Is there a way to force the update immediately so that the 3-letter code is changed, but the sub-form data doesn't disappear?

Thanks,

Jamie