The default selection policy, as DATA so an agent or host can reorder or trim it.
Order: an explicit user pick beats everything (the user is the authority on what the agent sees);
then the most recently started CAPTURE, because starting a camera or share is a deliberate "look at
this" and a surface is always there to come back to; then the focused surface; then simply the newest
source, so a lone unfocused surface is never invisible.
"Most recently started" is applied to captures rather than to every source. Applied to everything it
would always produce a winner and the focused-surface rule could never be reached.
The default selection policy, as DATA so an agent or host can reorder or trim it.
Order: an explicit user pick beats everything (the user is the authority on what the agent sees); then the most recently started CAPTURE, because starting a camera or share is a deliberate "look at this" and a surface is always there to come back to; then the focused surface; then simply the newest source, so a lone unfocused surface is never invisible.
"Most recently started" is applied to captures rather than to every source. Applied to everything it would always produce a winner and the focused-surface rule could never be reached.