It turns out that to control the menu1.checked property at runtime the setting is either True or False, not 1 or 0. However, it is possible to write the code as menu1.checked = 0 or menu1.checked = 1 and the desktop IDE does not complain at all about it. If you run your code via F5, your menu item toggles correctly. Even when you compile your program as a Pocket PC or Smartphone EXE, the program compiles without any errors reported. But when you run the program on the device and toggle that particular menu item, you do get an error. Like I said, witing the code so it reads menu1.checked = True or menu1.checked = False then the program works without errors on all desktop, Pocket PC or Smartphone. If use of True/False as opposed to 1/0 is required, then the desktop IDE should point out this error, when we run the program with F5 or at the very least when compiling.