I am using the web ide described in HANA XS development with the SPS07 Web IDE (focus on debugging) was working great.
The screen had a right-hand pane (as shown in that link) with the debugger options (stack, variables, etc).
At the right end of the row of buttons in that pane is "change layout". I pressed it - and the debugger pane disappeared.
How do I get the debugger pane back?