[Dev] Avoiding unnecessary notifictioans

[John Anderson]

A situation often occurs when updating the 
summary/sidebar/calendar/detail views in which you're responding to a 
user event, e.g. mouse or key event. Your event handler needs to change 
some data, e.g. move or delete an event then update the screen. After 
you've finished updating the screen we fall through to the idle loop 
where notifications are generated that tell you the data displayed in 
your view has changed. This causes another unnecessary complete redraw 
of your view -- which makes Chandler feel much slower than it really is.

To avoid this problem you should bracket your event handler/update code 
with calls to new routines on your block (stopNotificationDirt and 
startNotificationDirt) which will ignore notifications that dirty your 
block during the event handler. Make sure that after calling 
stopNotificationDirt you put all your update code in a try block which 
has a finally block containing the startNotificationDirt, so that it 
gets called even if an exception occurs.

I've already implemented this in Table, which is used in the Sidebar and 
Summary View and it made a big difference, so I suspect it could also 
make a big difference in the Calendar View.

John