Need either a formula or a code to keep a formula in a cell after it has been cleared

[porkchop101]

I have 2 cells both with comboboxes with dropdown lists.Both have vlookups & match in them.

If I select an item from the dropdown box in one the other is automatically filled in with the corresponding data.

The problem is once I have selected something in one it removes the formula from the cell behind it.

So when I need to make a change but have to use the other combobox it doesn't bring across the data automatically anymore.

Please help.