It’s very tiring to farm missions everyday and pass the mouse multiple times in the area just to check if you forgot a spot to loot.
Suggestions:
1) Highlight all the loot spots in the area by pressing a key, example: ALT key.
OR
2) Show in the upper-left corner “Loot Spots: 0/16”, 0 means the current looted spots and 16 the total amount of loot spots.