Blank Space at bottom of Polymer Paper Dialog - dialog

Question

I have a custom polymer dialog that I use for login, this is what I want it to look like:
This is the code I'm using to achieve that:
<polymer-element name="login-dialog">
<template>
<paper-dialog heading="XYZ Login" vertical autoCloseDisabled="true" transition="paper-transition-center" opened="true">
<p>{{feedback}}</p>
<paper-input floatingLabel label="Username" inputValue="{{username}}" type="text"></paper-input>
<paper-input floatingLabel label="Password" inputValue="{{password}}" type="password"></paper-input>
<paper-button role="button" on-click="{{reset}}" class="noink" affirmative>
Reset Password
</paper-button>
<paper-button role="button" on-click="{{login}}" class="ink" affirmative>
Login
</paper-button>
</paper-dialog>
</template>
<script type="application/dart" src="login-dialog.dart"></script>
</polymer-element>
I don't want the buttons to close the dialog, so I remove the affirmative from the paper buttons so that I can close the dialog myself if the correct login details were filled in.
As soon as I remove affirmative, a big white space appears at the bottom of the dialog:
Inside the dart code, I have the following for now:
login(event, detail, target) {
print("Clicked Login");
return false;
}
reset(event, detail, target) {
print("Clicked Reset");
return false;
}
I was hoping that returning false would stop the dialog from closing if I use affirmative, but it does nothing. Any ideas on how to get the buttons to no close the dialog unless I tell it to do so in the dart code and not have that white space at the bottom? (not keen on hacking it with css)

Answer 1

Returning false doesn't do anything. You need to call preventDefault() on the event.
login(event, detail, target) {
print("Clicked Login");
event.preventDefault();
// event.stopPropagation();
}
reset(event, detail, target) {
print("Clicked Reset");
event.preventDefault();
// event.stopPropagation();
}
<paper-dialog> has a specific option to disable automatic closing so you can affirmative for layout only.
<paper-dialog closeSelector="" ....
see also Prevent paper-dialog from automatically closing