Feature-Request: select initial position/size in shadow mode

[uli42]

On x2go-user a user described a scenario (see https://lists.x2go.org/pipermail/x2go-user/2020-May/006087.html) where he had 4 monitors connected to his (server) machine and an X server configured to display them in one row. Connecting to that machine from a client that had only one or two montors resulted in a display which was unusable because the remote was scaled down horizontally. The user was asking for a way to prevent that by selecting ONE remote screen and only displaying that on the client side, possibly combined with the viewport mode. In addition he had problems when manually switching to viewport mode because only the two middle monitors where accessible.

I think nx should switch to viewport mode automatically when the client side is unable to display the complete remote side without scaling.