For any case of 'Add New', choose to open a new window (popup) for entering data.
Figure: The 'Add New' button changes from a view into a data entry form
❌ Figure: Bad example - Bad Example - The 'Add New' button, shown in Figure 1, opened the page in the same window
It is better to open in a new form, reasons being:
However, you do need to call back on save and requery it. Use a modal form and requery it (DON'T use JavaScript, instead use the Modal Popup Form Example) An example of this is in Outlook with the 'New' button.
✅ Figure: Good example - Good Example - the 'New' button in Outlook opens a new form for you to construct your email
Figure: Adding a table in SharePoint have a popup with dimmed background