Wierd Data Duplication

[Dummy99]

Whenever I enter data in sheet1, the same data shows up in corresponding cells in sheet2.
Whenever I enter data in sheet2, the same data shows up in corresponding cells in sheet1.
I never had this in this same workbook before.

Why? How do I fix this?

Tks

[Dummy99]

I don't know what happened.
I tried to get rid of the problem in various ways but no success.
After I posted my problem, I returned to my workbook and the problem was no longer there.
It would still be good to know the cause and solution to this problem.
Tks

[Aardigspook]

You have probably grouped the tabs. Look at the tabs at the bottom of the workbook. Normally just one is highlighted. If you press Ctrl then another sheet, you'll see both the first and the new tab highlighted. If you press Shift then click another one, all the tabs between the first highlighted and the one you've just clicked will be highlighted. When the tabs are both highlighted like this, anything you do on one will be done on both/all of them.
Here's the relevant MS article: https://support.office.com/en-gb/art...6-cc92aec7b266

If you have all the tabs selected, click any tab except the current one will turn the grouping off and select just the one you clicked.
If you have more than one but not all, clicking any non-grouped tab will turn the grouping off and select just that one.

Hope that helps.