Hello,
In v2.5, on a tactical map, when a soldier is killed, the corresponding selection button ("1", ..., "12") is grayed and no more clickable. Sometimes, you just hear a scream during the alien turn, and a button becomes gray (a transient red message is displayed as well). If you don't use some external note (paper), you don't even know who's just died!
Suggestion:
Make the grayed selection buttons ("1", ..., "12") clickable, to display the name (and portrait) of the deceased (as when alive), possibly with a (skull) icon or a color code, and a red mark crossing the portrait (or display a skull portrait).