FAQ.How to collapse a window?
Feedback.

Answer: Use this function (Mac only):
Example:

Sub CollapseRBwindow(w as window, CollapseStatus as boolean)
  dim state, err as Integer
  dim wh as MemoryBlock
  
  #if Targetcarbon
    Declare Function CollapseWindow Lib "CarbonLib" (window as integer,collapse as Integer) as Integer
  #else
    Declare Function CollapseWindow Lib "AppearanceLib" (window as integer, collapse as Integer) as Integer
  #endif
  
  IF CollapseStatus THEN
    state = 1
  ELSE
    state = 0
  END IF
  
  err = CollapseWindow(w.MacWindowPtr, state)
  
End Sub

Notes:
Also the MBS Plugin has a window.collapsedmbs property you can set.
For Windows the MBS Plugin has a window.isiconicmbs property.