diff --git a/src/tilehighlight_type.h b/src/tilehighlight_type.h
--- a/src/tilehighlight_type.h
+++ b/src/tilehighlight_type.h
@@ -74,6 +74,8 @@ struct TileHighlightData {
 	ViewportPlaceMethod select_method;            ///< The method which governs how tiles are selected.
 	ViewportDragDropSelectionProcess select_proc; ///< The procedure that has to be called when the selection is done.
 
+	void Reset();
+
 	bool IsDraggingDiagonal();
 	Window *GetCallbackWnd();
 };
diff --git a/src/viewport.cpp b/src/viewport.cpp
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -2008,6 +2008,17 @@ static HighLightStyle GetAutorailHT(int 
 }
 
 /**
+ * Reset tile highlighting.
+ */
+void TileHighlightData::Reset()
+{
+	this->pos.x = 0;
+	this->pos.y = 0;
+	this->new_pos.x = 0;
+	this->new_pos.y = 0;
+}
+
+/**
  * Is the user dragging a 'diagonal rectangle'?
  * @return User is dragging a rotated rectangle.
  */
diff --git a/src/window.cpp b/src/window.cpp
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -1366,10 +1366,7 @@ void ResetWindowSystem()
 {
 	UnInitWindowSystem();
 	InitWindowSystem();
-	_thd.pos.x = 0;
-	_thd.pos.y = 0;
-	_thd.new_pos.x = 0;
-	_thd.new_pos.y = 0;
+	_thd.Reset();
 }
 
 static void DecreaseWindowCounters()