If you are using VFP 6 or 7, program(-1) returns the current program call stack level. From that, you can check if the previous level is from the "RefreshForm" method... if so, DONT force the extra instance to call again, skip it...

Func RefreshForm
  ..
  ..
  Call to your NodeClick()...
  ..
  ..
EndFunc

Function NodeClick
  ..
  .. your other code
  ..
  ** See if this instance called from RefreshForm 1 level back
  IF ATC( "RefreshForm", program( program(-1) -1 ) ) = 0
    ** must be from user clicking or other...
    ** NOT from the Refresh form method... allow call
    RefreshForm()
  ENDIF

  ..
  ..
EndFunc

HTH