Editor: remove tiles from painted zones, scrollable zone list

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/CAMPAIGN_EDITOR.md

@@ -95,7 +95,7 @@ The map in the game's 3D view; tool bar on the left, options on top.
 | Towers | arrow, cannon, magic, rune forge tower; the dungeon's or the knights', level 1–3 |
 | Traps | the seven traps and three doors, armed |
 | Forts | a knight fortress (with or without a shard), rival masters (Mossgrim, Lady Nightwell, rival 3); level = strength |
-| Zones | trigger zones: rectangle, circle (drag from the middle), painted tiles (paint onto the selected tiles zone), line (drag from start to end); name, rename, delete |
+| Zones | trigger zones: rectangle, circle (drag from the middle), painted tiles (paint onto the selected tiles zone; *Remove tiles* takes them out again), line (drag from start to end); name, rename, delete (the "x"); the list scrolls with the wheel |
 | Erase | removes units, towers, traps and doors on a tile |
 
 Options: brush size 1–5, rectangle, fill (connected area of the same ground), mirror (left/right,