Unexpected behaviour upon pressing the 'Enter' key on dialog screen

Hi.

I have two dialog screens that exhibit unexpected behaviour when i pressed the 'Enter' key.

Screen 1: When I pressed the 'Enter' key, the focus shifted to another input field and the content of the previous input field is cleared. The thing is, I did not have any codes in PAI for 'Enter'. Why is this happening?

Screen 2: On load, some of the fields on this screen will be disabled. However, when I pressed the 'Enter' key, all the disabled fields become enabled. Again, I did not have any codes that handle the 'Enter' key in PAI. Why is this happening?

Any help is appreciated.