As was recently noticed, RDP client screen size options were interpreted below the actual capabilities:

Fig.1. When editing Favorites, selection of hardcoded resolution did provide the options suitable for RDP 5.*, but not RDP 6.*. There was no issue when "Fit to screen" size option was selected.

Fig.2. This is the corrected resolution selection screen when editing Favorites. Local RDP client 5.* will cause available options to be limited to 1600x1200 session screen size, while RDP 6.* will support 4096x2048 maximum. Note that these client selected sizes can be overridden with the settings on the server or not supported in the first place. For example Windows 2000 Terminal Services are limited to 1600x1200 maximum session screen size. |