real-time mouse selection in vi

When I use putty to ssh into a machine without screen running, when I vi a file, I can click and drag out a region of text in real time. Each subsequent character highlights as I move the mouse while the left mouse button is held down.

However, when I do the same thing but within screen, it takes a second click to highlight the text and it does not highlight the text in real-time.  The region highlights only after the second click.

Any idea how to get the real-time selection working within screen?

Michael Grant