Bernard,
It doesn't need to be really transparent. Then there is another API to create irregular forms.
This is from VFP samples (using SetLayeredWindowAttributes):

* This technique only works in Windows 2000/XP but it is much more efficient
* than previous techniques of setting a bounding region for the form.

That previous techique was using:
CreatePolygonRgn,SetWindowRgn APIs which are also available on win9x.
Cetin

>Hi Cetin
>
>There is only 1 API in XP for this and that is SetLayeredWindowAttributes API.
>
>With this you can make a form and ALL its contents transparent. Or you can make a part of the form invisible. This way you can click through the form. I cannot see any use for a form that is invisible though.
>
>Only Vista has the API's to make part of the form transparent while keeping other parts opaque. The VFP sample shows a form and ALL contents transparent, not the form transparent and the objects on it opaque. To do that in XP requires some tricky coding - samples on my blog.
>
>
>>Hmm I wouldn't say it before checking samples. I remember I saw foxhead with the rest of form was transparent (well not transparent really -you can click on the form behind-, it was doable with winapi before VFP9 and 8 and I think the winAPI code exists here on downloads).
>>Cetin
>>
>>>Thanks Bernard!
>>>I will check it.
>>>
>>>>You cannot make only a part of the form transparent. It is either the complete form or not at all. This includes the form, and all controls it contains. The sample is part of the VFP sample.app in:
>>>>
>>>>c:\VFP\Samples\Sample.app
>>>>
>>>>However
>>>>
>>>>You could simulate this effect though by using an Alphachannel PNG.
>>>>
>>>>See:
>>>>http://weblogs.foxite.com/bernardbout/archive/2006/09/11/2436.aspx
>>>>
>>>>for a way to simulate a transparent area of a "form"