I have added a #submit handler to the default submit action on a node edit form:
$form['actions']['submit']['#submit'] = '_app_submit_to_usercart';
and it works correctly. But I then add a 2nd submit button as:
$form['actions']['save'] = [ '#type' => 'submit', '#name' => 'Standard Save', '#value' => t('Print and Mail Check'), '#button_type' => 'primary', '#weight' => 6, ];
and for some reason the submit handler for the submit button gets run for this button as well. I am sure in my handler I can act depending on which button was pressed; but wondering why I need to do that.
Apparently I am asking the wrong question. From my code above it seems that regardless of which button i click it is still submitting as if the main button is pressed. So question is how can i add another button (I have done this dozens of times in D7 and I thought a few times in D8; so not sure why this isn't working).