Excel formula-cell reference not working

[pbog]

I have a large formula in a spreadsheet and usually when I click in the
formula cell, the reference cells are color coded and I can then easily see
the cells in the spreadsheet that are referenced in the formula. with this
formula this isn't working. The formula stays the same and no cells borders
in the SS are color coded... Any one experience this problem or know how to
fix?

 

[JE McGimpsey]

What is the formula?

 

[Niek Otten]

Are you sure Excel sees it as a formula?

If you select another cell and look at your worksheet (not the formula bar),
do you see a result in the cell or do you see the formula?
Of course there are formulas with no precedents, like =NOW()

 

[pbog]

The formula is =I135+I137+I138+I139+I140+I141+I221+I279+I348+I349+I350....

Basically, adding 50 different cells (I've cut the list for space sake)...

The formula works and has worked. I'm working on a SS created by someone
else and just wanted to easily look at the cells referenced in this total.
I've done it MANY times before and it works w/in this SS for formulas w/o as
many cell references. Just can't understand why this one won't work.. I've
never heard of any limit to the number of cells allowed in a formula for this
option to work, and believe I've had other SS's w/ more cell references....
Thanks for any and all suggestions.