Tapping button to open dialog seems to trigger "tapped out side of dialog" (Mobile Safari)

[kenjitayama]

Dialog gets closed(canceled) while opening, when opened from a button tap, depending on button/dialog positions. Occurred in Mobile Safari but not in Mac Safari and Mac Chrome.

Additions to Polymer Starter Kit for reproducing:

index.html

<paper-button id="myPaperButton" on-tap="handleMyPaperButton">MyPaperPubtton</paper-button>
<paper-dialog
  id="myPaperDialog"
  entry-animation="scale-up-animation"
  exit-animation="fade-out-animation">

  MyPaperDialog

</paper-dialog>

app.js

app.handleMyPaperButton = function(e) {
  app.$.myPaperDialog.open();
};

app-theme.html

paper-dialog {
  width: 100px;
  height: 100px;
}

Making the paper-dialog large enough or adding no-cancel-on-outside-click stopped it from closing.