Polymer 1.x: Modal paper-dialog appears behind its backdrop - modal-dialog

Question

Does anybody have any advice for fixing the problem of a modal appearing behind its backdrop?
So far, I have tried making sure I have all the necessary imports (including <paper-dialog-scrollable>).
I also tried a "hack-fix" (suggested by someone) involving setting z-index: auto in the css of paper-header-panel. Neither works.
It's worth noting that the <paper-dialog> tag works just fine. Until I add the modal attribute.
Any ideas?
Similar issues
Appearing around the internet are this issue report and this Stackoverflow question.
my-element.html
<script src="http://www.polymer-project.org/1.0/samples/components/webcomponentsjs/webcomponents-lite.js"></script>
<link rel="import" href="http://www.polymer-project.org/1.0/samples/components/polymer/polymer.html" />
<link rel="import" href="../../../bower_components/paper-dialog/paper-dialog.html">
<dom-module id="example-element">
<template>
<!-- Dialog -->
<paper-dialog id="contactDialog" modal>
<h2>Login</h2>
<paper-dialog-scrollable>
<form id="contact-form" autofocus>
<paper-input autofocus id="name" label="Your Name"></paper-input>
<paper-input id="email" label="Email Address"></paper-input>
</form>
</paper-dialog-scrollable>
<div class="buttons">
<paper-button dialog-dismiss>Cancel</paper-button>
<paper-button dialog-confirm>Accept</paper-button>
</div>
</paper-dialog>
<!-- Button -->
<paper-button id="login"
data-dialog="contactDialog"
on-tap="openDialog">Login</paper-button>
</template>
</dom-module>
<script>
(function() {
Polymer({
is: 'example-element',
properties: {...},
openDialog: function(){
this.$.contactDialog.open();
}
});
})();
</script>

Answer 1

This is my solution:
openDialog: function(){
var body = document.querySelector('body');
Polymer.dom(body).appendChild(this.$.dialogId);
this.$.dialogId.open();
}

Answer 2

Special Note: This answer applies to those trying to implement a <paper-dialog modal> element inside a header element. Specifically, inside <paper-drawer-panel>.
Answer:
On this bug report rubenstolk provides a hack-fix as follows:
To implement #dhpollack's hack in a nice way, add this function to your custom element:
// https://github.com/PolymerElements/paper-dialog/issues/7
patchOverlay: function (e) {
if (e.target.withBackdrop) {
e.target.parentNode.insertBefore(e.target.backdropElement, e.target);
}
},
And add on-iron-overlay-opened="patchOverlay" to all your <paper-dialog>'s
I have tested it and verifies that it works. So for now, that solves it. Therefore, I suppose it is sufficient for now to wait until the bug is fixed.

Answer 3

It wasn't quite clear from the screenshot, but the problem is your modal dialog appears behind the <paper-drawer-panel>, yes?
If so, I believe the solution is the same here: just place the dialog or custom element containing the dialog outside of the <paper-drawer-panel>, e.g.:
<paper-drawer-panel>
<paper-header-panel drawer>
<paper-toolbar>
<div>Drawer</div>
</paper-toolbar>
<paper-menu selected="{{_selected}}">
<paper-item>Item 1</paper-item>
<paper-item>Item 2</paper-item>
</paper-menu>
</paper-header-panel>
<paper-header-panel mode="standard" main>
<paper-toolbar>
<h1>[[_selected]]</h1>
</paper-toolbar>
<neon-animated-pages selected="{{_selected}}">
<paper-button raised on-tap="openDialog">Show Dialog</paper-button>
<div>Div</div>
</neon-animated-pages>
</paper-header-panel>
</paper-drawer-panel>
<example-element id="dialog"></example-element>
Here is a screenshot illustrating this: