Add key swap feature for tab key to support Vino VNC connection from Windows
This is a very old issue (https://askubuntu.com/questions/839842/vnc-pressing-shift-tab-tab-only) that I somehow managed to fix for my system. It goes back to 2006: https://bugzilla.gnome.org/show_bug.cgi?id=353304#c21 . The suggested solution back than was to use xmodmap to force the Tab key to not use ISO_Left_Tab . Since xmodmap is not supported anymore in Ubuntu I managed to hack /usr/share/X11/xkb/symbols/pc to make this work on 18.04. This is not very elegant though. I think the best solution is to add this replacement option to
Additional Layout Options in gnome tweaks.