In D316, Vladislav has added support for tooltips specific to the currently hovered dropdown list item, specifically for victory conditions, maptypes and starting resources.
This patch adds item-specific tooltips for
* Population limit (since chosing a too big limit can often cause "lag" in both AI and multiplayer games. 4v4 * 150, 3v3 * 200 seems to work great, going beyond often caused lag. See also D232.)
* Map Sizes (since it isn't obvious which mapsize is best suited, see also rP18854.)
* Map filters (since it isn't obvious what the default or trigger filter contains.)
The map description could be displayed, but it is TLDR, not appealing and only distractive.
The structtree displays the history strings, but using them here also seems too noisy:
{F134459, width=1024}