Currently un-hide will always select previously hidden data.
While this is a good default, there are cases when you may not want this //(so it can be changed via the redo options or in the keymap)//
While a fairly straightforward tasks, this involves going over all unhide operators and adding this option.
//(Adding a boolean option to each operator, much the same way many selection operators have an **extend** option)//
Hint, you can find all the operators associated with unhide by searching `"\bHKEY\b.*\bKM_ALT\b"`