Motivation:
Users can't find the optaplanner annotations because they are hidden behind an icon that isn't related to planning.

Suggested implementation:
Take the OptaPlanner icon and monochrome the SVG to grayscale with Inkscape and then use it as the dock tab icon in the domain editor:

You can find the icon here:
SVG: https://github.com/droolsjbpm/optaplanner/blob/master/optaplanner-docs/src/main/docbook/en-US/images/Chapter-Planner_introduction/optaPlannerIcon.svg
PNG: https://github.com/droolsjbpm/optaplanner/blob/master/optaplanner-docs/src/main/docbook/en-US/images/Chapter-Planner_introduction/optaPlannerIcon.png