The toolbar contains all actions you need to configure and control the debug process. Items are described below from left to right as they appear in the toolbar.
When starting a debug session from the editor perspective using the Debug Scenario action, the state of this toolbar button reflects the state of the Show as XHTML output option from the scenario.
Turn on/off output to source
mapping - Enables or disables the output to source mapping between every
line of output and instruction element / source context that generated it.
Debugger
Preferences - Quick link to Debugger preferences
page.