How to block work order backflush booking to book more than planned quantity

As per standard process on Work Order Backflush Booking is warning you that you try to receipt more than the planned quantity.
It's very good that the system is warning you but you have no option to cancel to the exceeded booking.

The below script will help you to overcome this situation, it will display the warning message and block the posting

Paste below script on "fert_retrograd_abbuchen.src" project file

In case the user try to book more than planned quantity the system asks him "Check the Planned QTY" and blocks the program for continuing.
 
If you want a better warning text you can write after "Messagebox"
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windowevent prebackflushing
setvar=total_qty=%numadd(<dw_1.item.istmenge.value>,<dw_1.item.gesamtmenge.value>)
if <total_qty> n> <dw_1.item.sollmenge.value> then
   Messagebox= Check the Planned Qty
return false
end if
end event
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