using shader prevents color-change

I used a shader to adjust the size of a cicle depending on the percentage of the battery.
I also want to change the color when the battery is charging.

I've used this formula: '{pbc}' == 'Charging' and '1075d4' or 'af6718'

It works perfectly fine, until i turn on the shader. The block next to the color formula changes, but the graphic stays the same. When i disable the shader, the color change works again.