SyncMaster monitor solved


I had a big problem with my Samsung SyncMaster BX2031 and Raspberry Linux. I knew the monitor worked well with Ubuntu (this is my desktop).
So the solution was to reflash with uMate. Everthing worked ‘out-of-the-box’. The Wi-Fi keyboard, and the monitor.
I’m using an HDMI to DVI-D single cable into the Samsung’s DVI-D dual socket (and that’s working good too)

Raspberry Pi 3 Model B
Samsung SyncMaster BX2031
Logitech Wi-Fi Keyboard
USB Mouse


I am using UbMATE for Raspberry Pi 3 and have a video resolution problem: I cannot change (reduce) the resolution of the image in the screen. So I can only use my Pi with HD TV or good/newer projectors (data-show kind). I need it to work in a lesser resolution so I can work with other monitors and data-show projectors. I use my Pi to teach! (Godspeed GNU/Linux and Libreoffice in the classroom!).
Which is the easiest way to configure that? Is there an app?
The control panel does not allow me to change resolution. The screen properties neither. It is locked as it is. Years ago, when Ubuntu was on X11 and without systemD, Wayland, etc., things were better. Thanks.