View Offset Locked (SOLVED)

So i’m minding my own biz doing the usual work in Blender.
As I pan (like I have for over a decade) using Shift+Middle Click & Drag
Blender suddenly refuses to cooperate with me.
It displays the yellow triangle exclamation point message:

“View offset is locked”

The best part is there is no obvious way to unlock it,
or hint of how it even happened in the first place.

If this is a prank feature designed to stop a 3D artist in his/her tracks it is very successful.

Is there a way to unlock this…this…Blender virus (I joke)…without doing a factory reset or appending to a new file?

Thanks.

Nevermind I found it:

Shift + numberpad . to lock view
Alt + numberpad . to clear view lock.

What is the point of view lock?
What scenario would it be useful in?