Dual monitors using remote desktop

Microsoft Remote Desktop. Below is a screenshot showing that I select the option to use all monitors. That does cause the computer at work to extend to the second display, but my computer (the iMac) at home continues to use only the main monitor. If I drag something off the main home monitor, it disappears and cannot be retrieved. That is, it gets dragged to the secondary display at my work computer, which is not shown on my home computer's second monitor.

Thanks for the input. I will explore your suggestion, although I'm not very hopeful that it will resolve the problem. I work at a hospital and, for privacy/security reasons, they have the network very locked down (and I understand the need). I have contacted the hospitals IT help desk, but that function is farmed out to an independent contractor. They are only helpful, at best, with resolving the simplest issues. Otherwise, they simply function as message taking service. Because this issue is something that likely affects a very small number of people, it's difficult to get much traction. You've given me the most useful info I've received thus far, and I very much appreciate it.