Using Gui names :

  You will only ever need to give a gui's full path when you
  first load it with :

  >  GuiLoad  dh0:mypath/mygui.gc

  Note that if the gui is in the same directory as the gui from
  where you issue the GuiLoad command, you can :

  > GuiLoad  :mygui.gc

  and the path will be automatically substituted for the ':'

  Thereafter you can refer to the gui with only it's name:

  > GuiOpen mygui.gc

  If the command you issue exists in the same file as the gui 
  it wants to act upon, the you can use the "#This" keyword:

  > GuiOpen #This

  meaning - open the gui in which this command is located.
  This indirection is very usefull in many cases, such as when
  you want to change the gui name and do not want to change
  the GuiName in all the commands in the file. 

  It gives you more independent code, which is always good.

  If you want to load the same gui many times, you can also play
  around with the  GuiRename  command.