Messages code reservations

0xFFFFxxxx Reserved to system and systems libraries
	Details :
		OxFFFF1xxx Reserved to mouse events
		OxFFFF2xxx Reserved to keyboard events
		OxFFFF3xxx unused
		OxFFFF4xxx Reserved to notifications events
		OxFFFF50xx Reserved to common operations
		OxFFFF51xx Reserved to I/O Dialogs events
		0xFFFF5F0X Reserved to ComboBox
		0xFFFF6xxx Reserved to internal notifications	

Note on Mouse events :
	Use this operations to be sure it's a mouse event (DO NOT USE msg & OxFFFF1000)
		( msg & OxFFFF1000 == OxFFFF1000 ) 
	You can also use 
		!(msg & ~OxFFFF1000)
	