Validation List Stops working

[Guest]

I created a bunch of validation lists (data>validation>list). Mostly I
selected ranges but occaisionally I simply typed "Yes,No" in the dialog box.
The validations worked fine for a couple of days.
Now, the drop down list no longer works. I checked the validations and they
are still defined. I removed the validations then tried to reapply
them...still do not work.
Manual calculation is not turned on (automatic calculation enabled).
The sheet is not "protected"
The lists are on the same worksheet (and not hidden).
The lists and validated cells are not part of formulas.
Has anyone experienced a similar issue?

 

[Debra Dalgleish]

Perhaps objects are hidden. Turn show them:

Choose Tools>Options

 

[Guest]

Thanks...Show All is selected. No change...
I discovered I can right click and select from the pop-up menu "Pick from
drop-down List" and see the items...I just do not get the arrow on the right
edge of the cell indicating a list is present.