I created a custom.css file in the Yootheme template's css folder and added the following:
body.mceContentReset ::selection {
background: #ccc;
color: #000;
}
This file is loaded automatically by the editor.
This resets the selection style on the content when the Hight Contrast option is enabled in the Editor Global Configuration (which you have done).
I will include this selection reset as part of the High Contrast reset in the next update.
Ryan Demmer
Lead Developer / CEO / CTO
Just because you're not paranoid doesn't mean everybody isn't out to get you.