diff --git a/src/data/demloader.cpp b/src/data/demloader.cpp
index 8a7bb719..019ce7a0 100644
--- a/src/data/demloader.cpp
+++ b/src/data/demloader.cpp
@@ -10,7 +10,7 @@ static QList<DEM::Tile> tiles(const RectC &rect)
 {
 	QList<DEM::Tile> list;
 
-	if (!rect.isValid())
+	if (rect.isNull())
 		return list;
 
 	for (int i = qFloor(rect.top()); i >= qFloor(rect.bottom()); i--)