Description
https://developer.atlassian.com/design/latest/colors.html says
"Don't rely on color alone to convey state or meaning". The selected issue in GH boards is indicated by color only.
One other way to communicate this information might be for GH to make the border of the card thicker? The same problem exists with the colors of selected and unselected flagged issues.
This was also discussed at http://stackoverflow.com/questions/18241838/how-do-i-change-color-of-selected-issue-in-greenhopper-planning-board/18263886#18263886