Proper index creation for nested data

apps/opencs/model/world/idtree.cpp

@@ -171,10 +171,10 @@ QModelIndex CSMWorld::IdTree::index (int row, int column, const QModelIndex& par
         encodedId = this->foldIndexAddress(parent);
     }
 
-    if (row<0 || row>=idCollection()->getSize())
+    if (row < 0 || row >= rowCount(parent))
         return QModelIndex();
 
-    if (column<0 || column>=idCollection()->getColumns())
+    if (column < 0 || column >= columnCount(parent))
         return QModelIndex();
 
     return createIndex(row, column, encodedId); // store internal id

apps/opencs/model/world/nestedtableproxymodel.cpp

@@ -75,10 +75,10 @@ QModelIndex CSMWorld::NestedTableProxyModel::index(int row, int column, const QM
 {
     assert (!parent.isValid());
 
-    int rows = mMainModel->rowCount(parent);
-    int columns = mMainModel->columnCount(parent);
+    int numRows = rowCount(parent);
+    int numColumns = columnCount(parent);
 
-    if (row < 0 || row >= rows || column < 0 || column >= columns)
+    if (row < 0 || row >= numRows || column < 0 || column >= numColumns)
         return QModelIndex();
 
     return createIndex(row, column);