@zlefin Sorry it is confusing, forums is for players, issues is for developers. Use the forums to work out the details of how something should work, use issues to discuss with other developers how to code it.
This might be a difficult one to tackle, maybe not. I suspect it might be difficult due to the general cludginess of how the history is rendered. I will commend any effort, though you might be about to get knee deep in the swamp on this one : )
Do feel free to post any coding help/question/discussion items as needed, we will be eager to help you, help the project.
Of particular note in terms of behavior is the combat screen - you don't want it repeatedly coming up when you're trying to look at history; but if you're playing one of the nations in the game, and your input is needed, that's a much higher priority than if you're just a spectator.
FWIW - There is an option to show combats as an observer. It's somewhat hidden in the settings window and would do well to have a second home (a place to also toggle it) on the battle window itself.