Make sure tileset is added to the map when replacing a tile of an object

src/tiled/changemapobject.cpp

@@ -115,6 +115,18 @@ ChangeMapObjectsTile::ChangeMapObjectsTile(MapDocument *mapDocument,
     }
 }
 
+void ChangeMapObjectsTile::undo()
+{
+    restoreTiles();
+    QUndoCommand::undo(); // undo child commands
+}
+
+void ChangeMapObjectsTile::redo()
+{
+    QUndoCommand::redo(); // redo child commands
+    changeTiles();
+}
+
 static void setObjectCell(MapObject *object,
                           const Cell &cell,
                           const bool updateSize)

src/tiled/changemapobject.h

@@ -96,8 +96,8 @@ class ChangeMapObjectsTile : public QUndoCommand
                          const QList<MapObject *> &mapObjects,
                          Tile *tile);
 
-    void undo() override { restoreTiles(); }
-    void redo() override { changeTiles(); }
+    void undo() override;
+    void redo() override;
 
 private:
     void changeTiles();

src/tiled/tilesetdock.cpp

@@ -993,6 +993,15 @@ void TilesetDock::changeSelectedMapObjectsTile(Tile *tile)
     if (tileObjects.isEmpty())
         return;
 
-    QUndoStack *undoStack = mMapDocument->undoStack();
-    undoStack->push(new ChangeMapObjectsTile(mMapDocument, tileObjects, tile));
+    auto changeMapObjectCommand = new ChangeMapObjectsTile(mMapDocument, tileObjects, tile);
+
+    if (Tileset *tileset = tile->tileset()) {
+        SharedTileset sharedTileset = tileset->sharedPointer();
+
+        // Make sure this tileset is part of the map
+        if (!mMapDocument->map()->tilesets().contains(sharedTileset))
+            new AddTileset(mMapDocument, sharedTileset, changeMapObjectCommand);
+    }
+
+    mMapDocument->undoStack()->push(changeMapObjectCommand);
 }