Sectioning in legend

[Anasmasuris]

Hi, looking at the legend with all combined icons for all countries, I think that adding a different method of sectioning the legend could be more readable - country abbreviation in parentheses kind of disappear in all that text.

Thus I propose adding subtitles as a divider between groups of signals present in the legend. For further development, I would be nice to show only those features, which are present in given map box (similar to what QGIS legend does):

(Something similar to this below, content out of context:)