>>WAIT WINDOW 'Yada Yada' NOWAIT NOCLEAR AT yourX, yourY
>>
>>If that doesn't suit your needs, you must create your own.
>
>How to calculate yourX, yourY from form properties (position and size) ?
>
>User can move form in screen so hard-coded values cannot used.
>
>Message size if fixed: It has 3 lines and every line as approx 15 characters.
>
>Form properties are in pixels but wait window requires characters.

As I wrote, you must clearly create your own function for this. Should be fairly easy, though.