number of items however the if statement used nIHeight (just the
height of 1 item) and not nHeight (the height all the items).

comctl32: toolbar: Copy bitmaps with CopyImage so that it works also for DIBs (based on a patch by Oleg Krylov).

as it is mandatory and doesn't indicate that the arguments will be
passed in as named ones.

if it is not an HRESULT value, instead of getting it from a [retval]
attribute.

oleaut32: If an error info object was created when the invoked method failed then fill in exception info from the error info object.

so that the right external reference count is released when the proxy is destroyed.
Protect all changes to refs in the ifproxy using interlocked functions 
and update the thread-safety documentation.