>>I think - short test over here, verify if used - you can find the user's setting in the registry
>>

>>HKEY_CURRENT_USER\Control Panel\Desktop\DragFullWindows
>>
>>0 = Off
>>1 = On
>>

>
>But even if I can find it, it's not appropriate for my app to change it.

Maybe halfway? Deactivate it when your app gains focus, restore when it loses it? Not really sure this would work (i.e. do Windows read this setting that often), but may be worth a try.