Hello!
I made a group row changing command, it works fine on my local machine, but it works very slow in Web Client, here is the code:

&AtClient
Procedure ResetQuantity(Command)
   For Each Row In Object.List Do
      Row.Quantity = GetDefaultQuantity(Row.Item);
   EndDo;
EndProcedure

&AtServer
Function GetDefaultQuantity(Item)
   Return Item.DefaultQuantity;
EndFunction

You request server in cycle. Try to plase cycle in server function.

Or use client only.

Sounds reasonable, thanks, Mikhail!

Instead of &AtServer use &AtServerNoContext