$EM_EXGETSEL causes wordpad to crash

[Guest Floater]

Hi

I am trying to monitor text in notepad and wordpad as they are typed using 'SetWindowsHookEx'on $WH_KEYBOARD_LL. On $WM_KEYDOWN I use

$hWnd = ControlGetHandle("", "", "")

to get the handle for the current control.

The following part of code

$wparam = DllStructCreate("uint Start")
$lparam = DllStructCreate("uint End")
_SendMessage($hWnd, $EM_GETSEL, DllStructGetPtr($wparam), DllStructGetPtr($lparam), 0, "ptr", "ptr")

works perfectly well on both notepad and wordpad. But when I try

$tCharRange = DllStructCreate($tagCHARRANGE)
_SendMessage($hWnd, $EM_EXGETSEL, 0, DllStructGetPtr($tCharRange))

wordpad crashes. Could someone suggest the reason and a workaround.

Regards

Floater