Snapshot before repaint phase 2

Canvas.cpp

@@ -1,5 +1,6 @@
 #include "Canvas.h"
 #include "SxLog.h"
+#include "Window.h"
 
 static bool SxIsNoisyMsg(UINT m)
 {
@@ -432,6 +433,13 @@ void Canvas::onWindowResize()
 
 void Canvas::requestRepaint(Control* parent)
 {
+	if (shouldDeferManagedRepaint())
+	{
+		if (auto* host = getHostWindow())
+			host->requestManagedRepaint();
+		return;
+	}
+
 	if (this == parent)
 	{
 		if (!show)