Element UI version

2.15.1

OS/Browsers version

window7 chrome 69.0.3497.81

Vue version

2.6.12

Reproduction Link

https://codepen.io/charmkun/pen/abpbMmJ

Steps to reproduce

1. Trigger the colorpicker with predefine colors. Pick up a predefined color.
2. Click on the clear button (then colorpicker panel closed).
3. Trigger the colorpicker again and pick the same predefined color. Color can not be checked.

What is Expected?

All the colors can be checked after clear.

What is actually happening?

The color checked last time can not be checked after clear.