jQueryUI.button triggers click when form submits

jQueryUI.button triggers click when form submits

I found this is expected behaviour on old IE, but now hit it with latest broweser.

I have a form:
input[text] with datepicker,
input[text] with datepicker,
button with .click registered,
input[text] without any event connected

Everytime I press [Enter] on any input, button triggers click() event. Doesn't matter, whether I have submit() on that form or not.

How to avoid it? My button is a dropdown menu, triggered with .click(), so everytime I'm trying to submit a form with [Enter] I get dropdown menu pulled.

Is this expected behavior?