Message Box Question

[tmcquade]

I've written a program for adding feet-inches-fractions that requires that the variable containing the accumulation be cleared at the start of a new calculation.  I've written a key assignment to do this:

KEY KS_Bksp()

BEGIN

0▶ΣdFT;

MSGBOX("ΣdFT = 0");

END;

The problem I'm having is that after the message box is displayed and any key is pressed, the screen changes from the RPN home screen to the Function Symbolic screen.  Why does the screen change and how can I keep it from happening?