How to make a session that spans multiple monitors with Linux Receiver

Full-screen sessions span all monitors by default, but a command-line multi-monitor display control option, -span, is also available. It allows full-screen sessions to span multiple monitors.
Important: -span has no effect on Seamless or normal windowed sessions (including those in maximized windows).

The - span option has the following format:

-span [h][o][a|mon1[,mon2[,mon3,mon4]]]

If h is specified, a list of monitors is printed on stdout. And if that is the whole option value, wfica then exits.

If o is specified, the session window will have the override-redirect redirect attribute.

Caution: The use of this option value is not recommended. It is intended as a last resort, for use with uncooperative window managers. The session window will not be visible to the window manager, will not have an icon and can not be restacked. It can be removed only by ending the session.

If a is specified, Receiver tries to create a session that covers all monitors.

Receiver assumes that the rest of the -span option value is a list of monitor numbers. A single value selects a specific monitor, two values select monitors at the top-left and bottom-right corners of the required area, four specify monitors at the top, bottom, left and right edges of the area.

Assuming o was not specified, wfica will use the _NET_WM_FULLSCREEN_MONITORS message to request an appropriate window layout from the window manager, if it is supported. Otherwise, it will use size and position hints to request the desired layout.

The following command can be used to test for window manager support:

xprop -root | grep _NET_WM_FULLSCREEN_MONITORS

If there is no output, there is no support. If there is no support, you may need an override-redirect window. You can set up an override-redirect window using -span o.

To make a session that spans multiple monitors from the command line:

1. At a command prompt, type:

/opt/Citrix/ICAClient/wfica -span h

A list of the numbers of the monitors currently connected to the user device is printed to stdout and wfica exits.

2. Make a note of these monitor numbers.
3. At a command prompt, type:

/opt/Citrix/ICAClient/wfica -span [w[,x[,y,z]]]

where w, x, y and z are monitor numbers obtained in step 1 above and the single value w, specifies a specific monitor, two values w and x specify monitors at the top-left and bottom-right corners of the required area, and four values w, x, y and z specify monitors at the top, bottom, left and right edges of the area.

Important: You must define the WFICA_OPTS variable before starting selfservice or connecting to the Web interface through a browser. To do this, edit your profile file, normally found at $HOME/.bash_profile or $HOME/.profile, adding a line to define the WFICA_OPTS variable. For example:
??export WFICA_OPTS="-span a"

Note that this change affects both XenApp and XenDesktop sessions.
If you have already started selfservice or storebrowse you must remove processes they started in order for the new environment variable to take effect. Remove them with:

killall AuthManagerDaemon ServiceRecord storebrowse