GAT virtual machines use byobu.
Byobu has some useful features such as allowing a session to be split into multiple sessions within the same terminal window. Some terminal behaviour may be different from what you are used to, particularly navigation through scrollback in the terminal. Some key bindings are listed here including instructions for scrolling in the terminal.
Did your window freeze?: Try Ctrl-Q, this freezes a terminal.
F7 Enter scroll mode
Enter, Ctrl-C Exit scroll mode
Up/Down Scroll up/down one line while in scroll mode
PgUp/PgDown Scroll up/down one page while in scroll mode
Fn+Up/Down (Mac users) Scroll up/down one page while in scroll mode
More byobu keybindings (from https://github.com/dustinkirkland/byobu/blob/master/usr/share/doc/byobu/help.tmux.txt)
F1 * Used by X11 *
Shift-F1 Display this help
F2 Create a new window
Shift-F2 Create a horizontal split
Ctrl-F2 Create a vertical split
Ctrl-Shift-F2 Create a new session
F3/F4 Move focus among windows
Alt-Left/Right Move focus among windows
Alt-Up/Down Move focus among sessions
Shift-Left/Right/Up/Down Move focus among splits
Shift-F3/F4 Move focus among splits
F6 Detach session and then logout
Shift-F6 Detach session and do not logout
Alt-F6 Detach all clients but yourself
Ctrl-F6 Kill split in focus
F7 Enter scrollback history
Alt-PageUp/PageDown Enter and move through scrollback
Shift-F7 Save history to $BYOBU_RUN_DIR/printscreen