paper-spinner inside paper-button should be absolute positioned

[ShaggyDude]

Description

paper-spinner inside paper-button causes adjacent buttons to not line up (the margins are changed)

Expected outcome

The visibility of the spinner should not affect the margins on the buttons

Actual outcome

The visibility of the spinner makes the buttons not line up

Live Demo

second to last demo here... https://www.webcomponents.org/element/PolymerElements/iron-form/demo/demo/index.html

Steps to reproduce

1. Second to last demo above
2. fill in the data and click

Browsers Affected

• [x] Chrome
• [ ] Firefox
• [ ] Safari 9
• [ ] Safari 8
• [ ] Edge
• [ ] IE 11