Here's the relevant code:static FLOAT64 FSAPI getSwitchPos(FLOAT64, ID, PCSTRINGZ, MODULE_VAR *, PGAUGEHDR){ return genSwitchPosition;}MOUSE_TOOLTIP_ARGS(switchArgs) MOUSE_TOOLTIP_ARG(MODULE_VAR_NONE, 0, NULL, NULL, NULL, getSwitchPos, NULL, NULL)MOUSE_TOOLTIP_ARGS_ENDMOUSE_BEGIN(generatorSwitch_rect, HELP_NONE, 0, 0) // Toward RESET MOUSE_PARENT_BEGIN(0, 0, 75, 65, HELP_NONE) MOUSE_TOOLTIP_TEXT_STRING("genSwitchPosition: %1!d!", switchArgs) MOUSE_CHILD_FUNCT(0, 0, 75, 65, CURSOR_UPARROW, MOUSE_LEFTSINGLE, clickUp_mcb) MOUSE_PARENT_END // Toward ON MOUSE_PARENT_BEGIN(0, 85, 75, 65, HELP_NONE) MOUSE_TOOLTIP_TEXT_STRING("genSwitchPosition: %1!d!", switchArgs) MOUSE_CHILD_FUNCT(0, 0, 75, 65, CURSOR_DOWNARROW, MOUSE_LEFTSINGLE, clickDown_mcb) MOUSE_PARENT_ENDMOUSE_ENDThanks,Patrick

Your callback function is returning a FLOAT64, but your tooltip string is formatted to expect an integer.Doug

Yes, I caught that shortly after posting this, and changed it, but still didn't work.I'll have to re-read the SDK and look at it again when I'm more awake.Patrick

This code is tested & working:FLOAT64 FSAPI mouse_ipc (FLOAT64,ID,PCSTRINGZ,MODULE_VAR *MODULE_VAR_NONE,PGAUGEHDR){ return IPC_Active;}MOUSE_TOOLTIP_ARGS (E4) MOUSE_TOOLTIP_ARG (MODULE_VAR_NONE, 0, NULL, NULL, NULL, mouse_ipc, NULL, NULL)MOUSE_TOOLTIP_ARGS_ENDMOUSE_BEGIN(ipc_test_mouse_rect,0,0,0) MOUSE_TOOLTIP_TEXT_STRING ("IPC Control Status: %1!1.0f!", E4) MOUSE_CHILD_FUNCT(1,1,55,74,CURSOR_HAND,MOUSE_LEFTSINGLE,dump_mouse_cb0)MOUSE_ENDThe only difference I can see is that your function is declared as a static.Doug

Thanks Doug, I'll give this a try later today. I took a much needed day off yesterday, and now I have my brain back.Patrick

You guys will get a laugh out of this.I figured out why I couldn't get dynamic tool tips to work. :-beerchugI turned them on in Options. :-xxrotflmao