Param refresh doesn't accept input, never disappears

When changing the RNGFND_ORIENT parameter (a new parameter that I'm adding probably to AC3.5) from "25" to "0", a little window popped up saying, "A Param refresh is required - Please press F5 old #754 new #755".

I'm not sure why this appeared but in any case, the window never goes away even if I press F5. I need to close the window with the little "x" on the top right of the window.

Reproduce the issue in Mission Planner by changing RNGFND_ORIENT from "25" to "0" and observing the Param refresh window. Investigate the refresh prompt and its F5 handling; done means the prompt responds appropriately and disappears after the required refresh.

Written by the indexing model from the issue text.