Breakpoints/Tracepoints
The XSL/XQuery | Breakpoints/Tracepoints... command opens the XSLT Breakpoints / Tracepoints dialog, which displays a list of all currently defined breakpoints and tracepoints (including disabled breakpoints and tracepoints) in all files in the current debugging session.
The check boxes indicate whether a breakpoint or tracepoint is enabled (checked) or disabled. You can remove the highlighted breakpoint or tracepoint by clicking the corresponding Remove button, and remove all breakpoints by clicking the corresponding Remove All button. The Edit Code button takes you directly to that breakpoint/tracepoint in the file.
Use the down arrow 
to move the highlighted breakpoint to the Tracepoints pane and the up arrow 
to move the highlighted tracepoint to the Breakpoints pane.
In the XPath column in the Tracepoints pane, you can set an XPath for each tracepoint.