Hands-on examples:

Virtual Linac
	- Download and install:
		https://www.aps.anl.gov/epics/download/examples/vlinac_2013-04-12.tgz
	- Start "MEDM Virtual Linac"
	- Start "Start Virtual Linac"
	- Play with Virtual Linac

Run MEDM in edit mode:

	- Copy VirtualLinac/startMedm to VirtualLinac/startMedmEdit, and edit
	  so that MEDM starts in Edit mode.  Note that you must delete not only
	  "-x" but also "-macro ..." to run MEDM in edit mode.

	- Run startMedmEdit
	
	- We can't launch Virtual_Linac.adl directly from MEDM in edit mode,
	  because it contains macros.  Instead, we must launch it from a
	  related display.

	- Use "File/New" and "File/Save As" to make the display "top.adl"
	
	- Add a related display widget that calls up the Virtual_Linac.adl
	  display and supplies the macro "user" to it.
	  RightMouseButton/Object/Controllers/Related Display

Explore MEDM menus, tearoffs, RightMouseButton menu.

Play with MEDM
	- Add a "Graphics/Text" widget to top.adl
	- Add a "Monitors/Text Monitor" on "$(user):GV1:positionM"
	- Add a Text Entry for "$(user):H1:setCurrentC"

Exercises:

1	Make a disposable copy of Virtual_Linac.adl with which to play.

2	Look at "Beam On !!!" static text on Virtual_Linac.adl to see how one
	form of dynamic visibility works.

3	Make a new Graphic/Text object that is visible only when the beam is on
	"$(user):gunOnC" and the gate valve "$(user):GV1:positionM" is open.
		- Start with a copy of "Beam On !!!"
		- Use visibility mode "calc", rather than "if not zero"
		- Add the calc expression "a!=0" and test for beam on only
		- Add "$(user):GV1:positionM" as variable B
		- Change the calc expression to include "a!=0&&b==VVV"
		- Use "RightMouseButton/PV Info" to discover the desired numeric
		  value VVV of "$(user):GV1:positionM")

4	Make a new display, PM.adl, containing position monitor fields
		"$(user):PM1:intensityM"
		"$(user):PM1:XpositionM"
		"$(user):PM1:YpositionM"
	copied from Virtual_Linac.adl.  Size the display so that is has
	minimal extra space.  Edit all occurrences of "PM1" to "PM$(N)". 
	This display can now be used for any position monitor.

5	Make a new display, Two_PM.adl, and edit the related display widget in
	top.adl to call it up and supply the macro "user=xxx" to it.

6	Add two copies of PM.adl to Two_PM.adl
		- Make a rectangle
		- Group the rectangle
		- Note that the Resource Palette now contains a "Composite File"
		  entry.
		- Edit the "Composite File" entry, specifying
		  "PM.adl;user=$(user),N=1"
		- Make a second copy in the same way, this time specifying "N=2".