Re: What is the purpose of _NET_WM_USER_TIME?

[Joseph Krahn <joseph krahn gmail com>]

Overall, the current USER_TIME method is not really problematic.
However, a Window Manager specification defines methods to interact
with the Window Manager, and it seems a bit inappropriate to require
clients to actively maintain data for the WM. I just think there
should be a better design for the long term. Part of the problem is
that X11 was designed around the idea that the WM manages windows, and
doesn't have a good interface for the WM to handle input focus. Maybe
we need a standard X extension that gives more focus control to the
WM, and eventually make it a required extension, or make it a standard
part of X.

For now, I still think there could be a better approach. I though that
the WM could always monitor input events for the focus window, but the
X.org server apparently does not allow access to ButtonRelease events
outside of the focus window.

The original USER_TIME was modified to support a USER_TIME_WINDOW to
avoid waking up processes that monitor PropertyNotify events. Instead
of also requiring every client to create a USER_TIME_WINDOW, I think
it would be more efficient to use a common USER_TIME_WINDOW, which is
maintained by clients to hold both the Window ID and the event time of
the last user-input event. But, that depends if USER_TIME's only
purpose is to find the last input-event to avoid focus stealing.

Joe Krahn