A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I just have to say that this is not good enough. Taking away a feature then offering a work around that doesn't even work (I'm already running a multiple instances tweak to make it excel usable with multiple spreadsheets in the first place). I previously used this function multiple times a day. Now my only option is sum, quickly memorise the number, switch to the other spreadsheet, type it in before I forget it, then check I got it right. With all the distractions you get in your average office (and every other number in your head), this is a major pain and error prone.