Capturing GUI Events

What are you using to display the playlist? I'd assume you are using list boxes. List boxes should return EVENT_GADGETSELECT with single clicks and EVENT_GADGETACTION with double clicks and EVENT_GADGETMENU with right clicks.
This program shows this in action.

Strict
Global Window:TGadget = CreateWindow("Test",10,10,640,480)
Global List:TGadget = CreateListBox(20,20,400,300,Window)

AddGadgetItem(List,"First")
AddGadgetItem(List,"Second")
AddGadgetItem(List,"Third")

Repeat
	WaitEvent()
	Print CurrentEvent.ToString()
	Select EventID()
		Case EVENT_WINDOWCLOSE
			End
		Case EVENT_GADGETSELECT
			Print EventData()+" was single clicked"
		Case EVENT_GADGETACTION
			Print EventData()+" was double clicked"
		Case EVENT_GADGETMENU
			Print EventData()+" was right clicked"
	End Select
Forever

If that doesn't work for you, make sure your version of BlitzMAX is properly installed, upgraded and syncmodded.