Going to need to see the code in your Double Click event before we can even begin to troubleshoot your problem.

This is what  have.  It is adding the item to the subform on the parent form.  Now the issue is that the the record seems to be stuck in edit mode. i.e. the pencil stays in the record selector.  I have tried me.refresh in the after update event if ItemId field.  The only way to get it to clear is to hit the escape key, and then click off the record.  I hope this makes sense.

You need to Refresh the record in the subform.
After you have added the item add this line of code:

frmOrderDetail.Form.Refresh

i added the line and got this error, I also included a screen shot of the portion of the form

Hello, I have changed the way I'm doing this.  I removed the list box off the parent form and added a combo box with a button to the subform.  Just how Richard showed us in his TechHelp extended cut video.  Works flawlessly now.  Thank you for your help.  I was wondering if anyone knows which lesson he has for looking up if the item is already in the record set, and then increase the quantity by one rather than adding another line item.  Thank you again.

Take a look at the DLookup and DMax videos

Also the Sequential Numbersand Sequential Annual Coding

I was able to get it all to work with a record set, thank you