OK, that's better but I'm still confused. Are you using the same form as a subform (embedded on another form) and as a regular form opened by the button?
When you have an embedded subform, you wouldn't be using an "add" button to open the subform, it would already be open and visible on the main form.
When you have a form or subform that is showing data and you open another form to show that same set of data, and you change/add data using the second form, when you close the second form, you will NOT see the changes you made even though they have been saved to the table. Why? When Access opens a form and loads the bound RecordSource table/query, it keeps the data in memory. So, the mainform or subform is showing the data that was loaded into memory when the form opened. When you now open a popup form, a NEW recordset is opened using the bound table/query. You now have TWO instances of the same data loaded into memory. One is old and one has been modified. One doesn't automagically update the other, although, Access does have a refresh option so that eventually, if you wait long enough, updated data will show on the original form but NOT newly added records. Why, well again we go back to the "load the recordset into memory" issue. If the recordset contains 5 records, you will eventually see changes made to any of those records or you might even see ###deleted#### if the record got deleted but you will not see any newly added records. The form must rerun the query to select the data again in order to see the new records.
I think your workflow is incorrect but I'm going to take a leap of faith and tell you how to fix the problem even though I would prefer that you change the workflow. In the button code, change the argument in the OpenForm method to Dialog. That stops the code in the first form at after the new form opens up. The new form does its thing and closes. Then execution picks up at the next instruction. That instruction should be ---- Me.Requery --- that tells Access to rerun the query and it will pick up all the updates as well as new records and also drop any deleted records.