RDP screen layout

I am having a hard time consistently setting the the Windows RDP screen resolution. It used to work well in the past, but now the settings don't seem to allow the resolution to be set when automatically detecting the Remote Desktop Manager Window size.

I want all my RDP sessions to be 1024x768. I want the session to fill the RDM windows size.

I can set "Remote Desktop Size" to "Current Screen size" and that satisfies the session filling the RDM window size.
But, when I set that I can no longer set the the resolution, and the resolution defaults to the server's settings.

If I set the "Remote Desktop Size" to "1024x768" the session comes up in a small window that does not fill the RDM window size.
No other settings seem to make if fit.