diff --git a/docs/ADDON_COMPAT.md b/docs/ADDON_COMPAT.md
index 6876b196..74bf918f 100644
--- a/docs/ADDON_COMPAT.md
+++ b/docs/ADDON_COMPAT.md
@@ -2990,3 +2990,28 @@ open something or create a frame and still have the scene settle around it. `$WO
 keeps the shutter, where a read and the pixels it explains come from the same frame. The deep-zoom
 shot needed the first: the tile mode has to be switched before anything draws, and a chunk at the
 shutter is a frame too late to appear in the image.
+
+### Carrying the switch to a save that already exists
+
+The default only reaches a fresh install. grom's `OpenMapClassic.lua` pins
+`["minimapTileMode"] = "fdid"`, and a saved value wins over a default, so the change would never
+have reached the one person it was made for. OpenMapClassic has a migration hook for exactly this
+(`Core.lua:255` calls `mod.Migrate(saved)` before the defaults fill), so the port edit adds one
+more entry beside its own six: a one-shot flip of `fdid` to `twm`, flagged so an explicit
+`/omc tilemode fdid` afterwards is respected. Verified: his saved file reads `twm` after a load.
+
+### The ladder, end to end
+
+Driven through `WorldMapButton`'s own wheel handler, thirty clicks out and forty back in:
+
+```
+start         scale=1.0000
+30 wheel out  scale=0.0330   <- the ladder's floor, the whole world
+40 wheel in   scale=2.3734   <- its ceiling
+ladder 0.0330 .. 2.3734 over 27 steps
+```
+
+Both ends reachable, which is what "scroll all the way out to the world map and all the way in to
+the minimap" asks for. Captured at zoom 1, 3, 9 and 40 with grom's own settings and no setup
+chunk: the world sheet with both continents, Eastern Kingdoms with its zones, Dun Morogh with its
+neighbours stitched in, and the minimap's terrain drawn through the map.