[ EXEC <command> | RUN <command> | ScreenRun <screen> <cmd> 
	 | UPDATE | LOADUPDATE | LOAD <file> [arguments]             
	 | EXIT [<string>] | QUIT [<string>]                         
	 | DumpX <variable> | DumpY <variable>                       
	 | LastX <variable> | LastY <variable>                       
	 | LastXPos <variable> | LastYPos <variable>                 
	 | Popup | PopupClose                                        
	 | Setenv <variable> <value> | UnSetenv <variable> ]         
	 ( ['command 1' 'command 2' ... 'command n'] )               


 The EXEC <command> option starts the <command>
 as if it had been started from a shell window. Example:
 Button "Show files" exec "list >con: S:"
  

 The RUN <command> option starts <command> with a "run >nil:"
 in front of it. So, these two lines are equal:

 button Hello run "selector hello.sel"
 button Hello exec "run >nil: selector hello.sel"


 The SCREENRUN <screen> <command> option works like this:
 If the public screen <screen> exists, then this screen is moved to front,
 else the <command> is started with a "run >nil:" in front of it.
 This is very comfortable, as you can make a button to get to a programs
 screen, regardless if it's open or not.
 
 Example:
 
 button DiskMaster screenrun DM.1 'dm2 sys:disk&fil/DiskMaster2'
 button Workbench screenrun Workbench

 Also see: wbrun
           A shorway to your panel