Update split_container.cpp

Author: gammasoft71

examples/xtd.forms.examples/containers/split_container/src/split_container.cpp

@@ -6,7 +6,7 @@ class form1 : public form {
     text("Split container example");
     client_size({300, 300});
 
-    split_container_left.parent(*this);
+    split_container_left.parent(self_);
     split_container_left.dock(dock_style::fill);
     split_container_left.panel1().back_color(color::light_blue);
     split_container_left.splitter_distance(70);