Performance problems with Firefox older than Version 56

[MarEliSeg]

Description

It takes about 3 seconds to open the color-picker-field, if you click on the paint bucket icon.
After choosing the color, it takes a few seconds until the color is selected.

Live Demo

https://www.webcomponents.org/element/PolymerElements/paper-swatch-picker/demo/demo/index.html

Steps to reproduce

1. Start paper-swatch-picker on Firefox older than 56
2. Click on the paint bucket icon
3. Select color

Browsers Affected

Only tested with Firefox.

• Chrome
• Firefox
• Safari 9
• Safari 8
• Safari 7
• Edge
• IE 11
• IE 10

[FabianWilms]

Any news on this? We currently have the same problem.