[plt-scheme] DrScheme Debugger not showing values of variables or expressions.

Hi,

I'm trying to use the DrScheme debugger but I'm not seeing the values
of variables to the right of the debug buttons, nor the result of
expressions to the left of the debug buttons.  (I'm seeing neither of
these anywhere else, either.)  This is not what I expected given the
following excerpt from the manual.

"When the program is paused, move the mouse over a variable to display
its value in the debugging panel to the right of the buttons. When
pausing at an expression's result, the result is shown to the left of
the debugging panel's buttons, and the result can be changed by
right-clicking the pause point."

I'm running DrScheme 370 on Windows.

Thank you.

-Ethan Herdrick