Thank you Ben,
may I ask you to try the very first version of sudoku in post #32?
It was reported to be working, but will freeze the touch-interface on exit, because of the missing loop-breaking code.
If the HOME button isn't working it seams that the code breaks any where in init.
It is proof of concept, that you can define a "system do-functuion" just in JS-code, without notice it in the XML. (See doHold# in FreeCell for instance)
Or just a second thought: It seams that the reader had to go thru a full restart cycle before accepting modified code. (You have once deleted a try-catch block from startup-code, which couldn't have done any harm, and got the App working afterwards)
Regards
Mark