virtualbox.org

From what I gather in other posts, am I right in thinking that mouse control is always with the host, even when guest additions are being used?...

If I have a Windows Guest running on a Windows Host, and the host is running a program that manipulates the mouse, for example, can the program on the host effectively move the mouse and click in the Guest OS?

I hadn't noticed but guest additions must have been incorporated at some point - I just installed a fresh Win XP and the mouse integration works fine out of the box.

To get back to my question, I had a dig around and found some code I could reuse, and the answer is YES!

I only tried it with Windows Host and Windows Guest, but yes the guest's mouse can be used from the host.
The only snag I did find was that I had to add a delay between setting the mouse position and the mouse click, otherwise the click was not actioned.