Using variables for index values in mapping to arrays

Hello World,

Today I was able to loop through a record list and map each element to another record list using the $iterator variable as my link/properties/indexing for my target recordlist.

Now it appears that when i try to enter a variable as my link/properties/indexing variable, the developer is not saving my variable when i exit the dialog. The dialog will only save integer values as the index.

What made the developer allow me to use a variable in the first place for my link/properties/indexing varibale.?

Please adivse.