Update Migration Guide doc

cztomczak · cztomczak · commit da3fab41a3b9 · 2018-08-28T10:37:00.000+02:00
diff --git a/docs/Migration-guide.md b/docs/Migration-guide.md
@@ -156,7 +156,9 @@ implementation in `src/dpi_aware_win.pyx`.
 
 This function can sometimes cause app hanging during window resize.
 Call instead the new `WindowUtils`.[UpdateBrowserSize](../api/WindowUtils.md#updatebrowsersize)
-function.
+function. Except when you use the `pywin32.py` example, in such case
+`WindowUtils.OnSize` must be called. See [Issue #464](../../../issues/464)
+for details.
 
 
 ## v49+ Notify CEF on move or resize events
