I suppose your form's name as my_form

Define Bar 1 Of resv Prompt "Sales" KEY F3,"F3" Picture "1EARTH.GIF" skip for wexist("my_form")

>my menu is defined as below
>

>Define Popup resv Shadow Margin Relative Color Scheme 4
>Define Bar 1 Of resv Prompt "Sales" KEY F3,"F3" Picture "1EARTH.GIF"
>Define Bar 2 Of resv Prompt "\-"
>Define Bar 3 Of resv Prompt "Sales Return" KEY F4,"F4" Picture "1EARTH.GIF" Define Bar 4 Of resv Prompt "\-"
>Define Bar 5 Of resv Prompt "Purchase" KEY F5,"F5" Picture "1EARTH.GIF"
>On Sele Bar 1  Of resv Do Form sal2
>On Sele Bar 3  Of resv Do Form sr2
>On Sele Bar 5  Of resv Do Form pur
>READ EVENT
>

>when i press F3 my form "sal2" open again and again but i want to open this form only one time and if the form already open is should not reopen, only active.
>
>warm regards,
>mk.