Clicking/Mouse problem

Im haveing a clicking problem that on creative right click dups and left click splits and object in half. i need to fix the spliting problem cus i have to move each block in it then click them all in idvasulalyits so annoying it made me almost quit playing

I was expecting it to run likein 1.3.2 cus the bug doesent happenin 1.3.2

Steps to Reproduce:
1. Left click a iteam in 64 stack and it will give you 32 and thn 16 then 8 then 4 then 2 then 1