Getting out of a full-screen Citrix session in Linux

If you're running the Citrix ICA client under Linux and your Citrix session runs in full-screen mode, you can press Ctrl-F2 to pass the following keystroke to the host Linux desktop rather than the Citrix session. For example, if the Citrix session is connected to a Windows desktop, then pressing Alt-Tab in full-screen mode will normally send the Alt-Tab to Windows. Pressing Ctrl-F2 followed by Alt-Tab will send the Alt-Tab to the Linux desktop instead.