Protect against multiple authors performing simultaneous saves to a Scenario

[#1]

Description -

Person A is editing a scenario.  Person B starts editing that same scenario.

Person A saves the scenario with changes.  Person B then saves the scenario with changes.

Person A's changes are lost.  Person B was unaware that Person A was (1) actively editing and (2) had saved.

This is a common problem with online tools.  Some suggested solutions including (1) tracking user activity and warning other editors that someone else is ALSO looking into the file and/or (2) warning a user that someone else has saved the scenario since the scenario was opened for editing and that changes might be overwritten and/or (3) allowing an editor to "lock" the scenario for a defined amount of time so they are the only ones that can edit.

Why is this feature important to you -

The "simultaneous overwrite problem" is real and has forced us to have to re-do work.

How would you like the feature to work -

Ideally, I'd like for a simultaneous edit canvas like Google Docs provides.  But I'll accept some type of warning and/or "lock" behavior similar to what Microsoft Sharepoint provides.

Current Behaviour -

See Description above.