It took way too long but I found a solution for the xpanel kiosk mode bug.
I was having a weird issue with 'phantom' button clicks when it was in kiosk mode. The problem went away if I put it in full-screen.
After some tinkering and google-ing the problem here are the new xpanel.ini settings.
  • left=-4
  • top=-50
  • right=1028
  • bottom-772
That completely fills the screen at 1024x768