yogi_Dynamically Highlight Duplicate Entries in Column A Across All Tabs (Sheet1 Sheet2 Sheet3) Of A Spreadsheet

                                          Google Spreadsheet   Post  #1444
Yogi Anand, D.Eng, P.E.      ANAND Enterprises LLC -- Rochester Hills MI     www.energyefficientbuild.com.   Dec-24, 2013
question by 13245DM (http://productforums.google.com/forum/?zx=fvgkvgqvpzi3#!mydiscussions/docs/6RUZSlMx3nI)
Find duplicates in across multiple sheets and locate and highlight duplicate

Hello,

I have provided a link to my sample sheet.

https://docs.google.com/a/fugal.com/spreadsheet/ccc?key=0Apur2TIv2WbtdDJ0S3plUDdQZURTenVYcjlTd0RwSWc&usp=drive_web#gid=0

My objective is to avoid any duplicates in column A, across all tabs. If there are any duplicates, I would like to see an error message (like data validation in excel using a customer formula). 

I would also like to highlight any duplicate address.

Any help with this would be great!!!!

Thanks

-----------------------------------------------------------------------------------------------------------------------
I have used Google's New Sheets made available in the second week of December 2013 because it allows formula based Conditional Formatting.