If you create a TAB application and put one parameter in the header, as PAR1 in this example:
The same paramter is correcly recognized as an IN paramter (even if in lowercase, which I think is a bug in the bug)
but cannot be seen as an IN parameter from any other application.
If you try, for instance, to create a grid linked to the Tab app, parameter PAR1 is not presented during the link creation. See screenshot below:
