drop down in toolbar problem

I have added button on a toolbar with the style of dropdown.
my problem is that I want the drop down menu to open even when I click on the parent button.

Do you experts know how can it be done ?

I suspect you can do it with the SendMessage API using WM_COMMAND (&H111), but even having searched around on the Internet I can't find out how.

Thanks trisuglow for your effort,
I can't find it either.

Any other suggestions ?

To generate a pop-up menu, use the TrackPopupMenu API

See this thread