Wrong error popups on "Add new record" forms

To reproduce the error:

1. Click on "Add new record" button under any tab.
2. Click save without filling the fields.
3. Look at the error messages in the black boxes in the up right corner of the screen. (which is correct)
4. Press "Esc" key to close the form.
5. Repeat step 1, 2 and click save without filling the form.
6. Notice that it shows the alert box rather than the messages in the black boxes.