I Cannot unhide my sheet!?

[KroogerFx]

Hello, so I have a main sheet that has drop down boxes on it, I made a second sheet that had big lists on it to use for the drop down boxes on the first sheet. I am now having to go back and change these lists but since I hid the second sheet it is not there and when I goto unhide it I can't because the unhide sheets button us greyed out. The sheet must still be there because the drop boxes still have all the lists in them.

I tried hiding the first sheet and then unhiding it and it worked and only the first sheet came back. Does anyone have an diea as to what happened to the second sheet? Thank You




EDIT:
I have confused Hiding a workbook and hiding a sheet
Any mod feel free to remove post