One can now bind the left/middle/right mouse buttons to on-click. In
fact, you can have all three buttons bound to different handlers for
the same particle. The new syntax is
on-click:
left: <command>
middle: <command>
right: <command>
Leaving one out is the same thing as not mapping it at
all. Furthermore,
on-click: <command>
is still valid, and is a shorthand for
on-click:
left: <commsnd>
The idea is, consumers of a tag, can check the realtime property, and
if set to something other than TAG_REALTIME_NONE, schedule a realtime
update.
For example, it could be used to track song progress.
