Hi,
I was looking at someone's profile and then clicked to send them a message.
The message screen/box opened behind the profile box.
This means that you have to delete the profile box to send the messages. Which in turn means you need to open the profile again to send an invite.
This may be linked to the open profile, click on company, select another person from the company and it opens behind everything else.
May just be ordering that require a tweak.