Identify from where a form has been opened

How can I - preferable using @Formula - identify where a form is being opened:

a) Normal/Standard Create->Formname

b) Opened inside a Composite Application as a view part

c) Opened in a sidebar as a widget

d) Opened in a browser

I can use @IsInCompositeApp to decide whether it has been opened in a+d or b+c.

I can use @ClientType to decide whether it has been opened in a+b+c or d.

But I can’t find a way to figure out how to distinguish between b and c.

Subject: Noone?

bump!