Blog Post
I realized that the difference in the 1920x1080 of the actual client and the way it's scaled up for display on my 4K monitor (up to about 2878x1614 or whatever, which was an approximation) is 150%. That's the scaling factor I have on my 4K display, so I think RDCMan 2.93 is scaling up the connection by the scaling factor I have set.
In v3.01 it's not doing any kind of scaling of the actual connection, and if I were to change the scaling factor in the properties of a connection, that's only changing the display scaling of the *remote* system which means I'm still getting a 1920x1080 sized window but with everything blown up larger in the same size box. :)
I hope I've explained the situation well enough to replicate.
This is the desired and "correct" behavior. The RDCMan window should maintain the geometry of the host system where you're running, while the remote system to render at various "zoom" levels - 100%, 125%, 150%, 175%, etc. This can be configured per remote connection, or per the entire group.