HP 48GX: How to edit existing equation in Equation Writer

[rbcam]

Is it possible to edit an existing equation in Equation Writer (EW)? I am using both droid48 and emu48, and I get the same behaviour with both.

I can easily create an equation (or expression) using EW. Once I have put the equation on the stack, however, I can't figure out how to resume editing it in EW.

If position 1 on the stack has an equation, if I press <down arrow>, the equation is shown "full screen". At this point, pressing the arrow keys or, e.g., the <+> key has no effect. If I press <ON>, the right-most element of the equation is highlighted, and the menu bar changes to RULES, ... I believe this is called Selection Mode.

At this point, pressing <+> has no result (except a beep).

So, from this state, is it possible to resume editing? Or is there another way to get into editing the equation, using EW?

Thanks

- richard