clipping feature?

If I set the axis limits to a value less than the actual domain of the data, the line is not extended to the edge of the plot but rather is only drawn to the final point within the domain. The following illustrates what I mean:

ax = subplot(111)
plot([1,2,3,4],'bo', [1,2,3,4],'k')

The plot stops at the point (2,3) although the data go to (3,4). When I have dealt with these issues, I usually draw the line to its full extent and then clip the line so it stops at the edge of the plot frame.

I set the axis bounds when I am plotting a number of lines some of which have a larger domain. While interested in the behaviour in the limited domain, I would like to retain the information that some lines extend beyond.
When I first encountered this behaviour, I thought that I had mistakenly truncated my input data - I think that the plot should show as much of the data passed to it as possible.

Is there something I am missing - or is this a feature?