Comment 123 for bug 93546

(In reply to comment #87)

> [...] If lock detected, place a flag somewhere in the gui
> or give a warning that is running read only. this "read only" mode is the
> limited functionality Harry (comment #86) said.

Don't be misled into thinking this is easy. The second instance would still need to have access to a consistent profile (whether real or emulated) and to be able to write to it, even if the changes will later be discarded when the instance exits. This requires a fundamental change to the way the profile is stored on the disk; all an emulation layer might achieve is to help reduce the effort involved in modifying all the existing code that makes use of the profile.