We got a report on Issue 13851 that reconnecting to a single monitor 1920x1200 session with a dual monitor 1920x1200 machine resulted in a 1920x1200 session centred across the edge between the two local monitors.
Did some local testing. Could not reproduce the exact reported problem, but got another one instead: Connections: closed: 127.0.0.1::53712 (Desktop configured a different screen layout than requested) The issue seems to vary depending on local WM. These are the results: System From To Result --------------------------------------------------------------- F17/Gnome 3 1920x1200 2 * 1920x1200 Fail F17/Gnome 3 1920x1200 1920x1200/1440x900 OK F17/Gnome 3 1600x1200 2 * 1600x1200 Fail F17/Gnome 3 1920x1200 1920x1200/1440x1050 OK C6/Xfce 1600x1200 2 * 1600x1200 OK
Also noteworthy is that this only happens the first time the session is resized to two monitors. After having been successfully resized to the 1920x1200/1440x900 combination, I could successfully switch back and forth between 1920x1200 and 2 * 1920x1200 (which previously did not work).
Managed to get what seems to be this bug with a 1280x1024 + 1600x1200 combo as well.
*** Bug 5359 has been marked as a duplicate of this bug. ***
I believe this bug is caused by this problem mentioned in ScreenSet.h: // FIXME: List order shouldn't matter inline bool operator==(const ScreenSet& r) const { return screens == r.screens; } inline bool operator!=(const ScreenSet& r) const { return screens != r.screens; } In my testing, I got "Desktop configured a different screen layout than requested" and with debug printing: server->screenLayout: VNCSConnST: 2 screen(s) 2007237709 (0x77a4044d): 1280x1024+0+0 (flags 0x00000000) 704877633 (0x2a039441): 1920x1080+1280+0 (flags 0x00000000) layout: VNCSConnST: 2 screen(s) 704877633 (0x2a039441): 1920x1080+1280+0 (flags 0x00000000) 2007237709 (0x77a4044d): 1280x1024+0+0 (flags 0x00000000) Thus, actually same but in different order.
I have fixed this upstream now: https://github.com/TigerVNC/tigervnc/commit/a9d7069f9c6185796a44c9790f6badd0b59124f9
Works well. I tested the following with a Fedora 28 client and Ubuntu 18.04 server: 1. Start a new 1024x768 windowed session 2. Go fullscreen over a single 1920x1200 monitor 3. Open options and change to fullscreen over all monitors, effectively adding the second 1920x1200 monitor This gets me disconnected with 4.9.0 but works fine with master.
