Lion's iCal changes default behavior of new event creation in Month View and creates all day events by default.
The single behavior in Lion that makes me grumble the most is the behavior in iCal when creating a new event in Month View (things work as before in day and week views). In Lion, when creating a new event by double clicking on the day the event is automatically assigned as an all day event. In most instances where an appointment is being created this will need to be changed.
The solution is that in Month view double click on the day you want to make the event on and then type 'Steve 9am' and it will correctly define an event called Steve that starts at 9am and ends one hour later.
You can even get fancy and define an event's length in the title, e.g. 'Steve 9am-2pm' and it will correctly set an event that starts at 9am and runs until 2pm.
One hour is the default length for an event, however if you would like to redefine the default length of all new events the command is:
defaults write com.apple.iCal 'Default duration in minutes for new event' 15
This makes event lengths default to 15 minutes, but you can use whatever value you wish.
[crarko adds: I tested this, and it works as described. Obviously to go back to the hour default length you can change the 15 to 60 in the above command.]
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