It's possible, but difficult because i have to compare two databases - and this is above browser storage limits in new, full universes. This is a task for serverbased projects which are using the OGame API - for example Galaxytool or UniverseView
do you think of an red background of the planet images? whatsoever, in a young univers there will be much of them...
once i suggested this C&H - destroyed planet and an resettlement is almost the same in the visualization.
But yea after the resettlement you cant see it anymore... maybe an red background can be shown after the strikethrough (and after the resettlement) for a periode of time --> it should not be shown for a nomal colonization (this can be highlighted in another color or not)