Setup:

• open 2 files
• switch between them

Today:

• we go to disk each time to check if the file on disk has changed

Proposed:

• show the file instantly without going to disk
• check for the file having changed in the background

The consequences are:

• files will load instantly when opened once during the session (good)
• if the file has changed on disk (and we missed the file event when this happened) it is possible that the editor is updated later (I think that is OK)
• if the user manages to make the file dirty before this update happens, the risk of seeing a save conflict (not ideal, but this is should not be the 99% case)

Overall this optimizes performance for the 99% case and especially remote editing scenarios where resource access is potentially slow.