Xubuntu 19.10

After the recent upgrade from 19.04 to 19.10, the xfce4-terminal was newly grabbing F11 and using it to toggle maximize/minimize.  This was not good because that key is used by me for various functions including mappings in the vim editor.  With some help from someone in the Xfce Forum, I discovered that the shortcut for this was apparently built-in, but controllable from the  ~/.config/xfce4/terminal/accels.scm  file.  There I found the commented out line:

; (gtk_accel_path "<Actions>/terminal-window/fullscreen" "F11")

and manually edited it to:

(gtk_accel_path "<Actions>/terminal-window/fullscreen" "")

I then started a new terminal and indeed, F11 was deactivated.  Nevertheless, when I next logged in, I discovered that F11 was once again active and that the accels.scm file had reverted to its original configuration.  After a lot if head scratching and searching for where else this setting might reside, I decided that the terminals were rewriting this file upon exit!  This meant that you cannot edit the xfce4-terminal configuration files from the terminals themselves!  Ultimately, I had to dismiss all of the running xfce4-terminals, start an xterm, and then edit the file.  This allowed the change to stick and now F11 is deactivated.

If this isn't a bug, it's a serious limitation and a source of great confusion.  Everything important needs to be editable from the Preferences so that the internal settings can then be written out if that is the model to be retained.   In the Preferences->Advanced->Shortcuts section, there should be an entry to disable F11, and entries for any other keys that the terminal wants to co-opt.

(BTW, in case it's related, I also noticed that the xfwm4 Window Manager suffers from something similar.  It can/does not currently save its changed Theme and if you manually edit the config file while the window manger is running, it will be overwritten when the manager exits.  Reported here:  https://bugzilla.xfce.org/show_bug.cgi?id=16398)