Crash happens when duplication a button with textBlock

i tried to show it here:

inside a vertical box ,
if i duplicate buttons having no child objects then everything works fine.
but problem happened whenever i attempt that with button having a text block inside it.

i did some debug.
most probably problem is in 568 line from:
Z:\UnrealEngine_4.7.2_release_Build\Engine\Source\Editor\UMGEditor\Private\WidgetBlueprintEditorUtils.cpp 's

Hi Muzaheed,

Thanks for report! I was able to reproduce this in 4.7.2, but it looks like it has already been fixed in our main internal build. fix should be available in a future release, most likely 4.8. Thanks!