Tree view order nodes before leaves

Hi,

I want to use a tree view as a navigation system, and my windows are arranged for some in sub folders and for others directly on the root node
The issue is that, even though the Auto Sort is Flase, the nodes (folders) are always shown above the leaves

I can change the display order of the folders or of the leaves, but I cannot move a leaf above a folder.

image

Code of the create menu function, (custom method of the tree view):

	headers = ["path","text","icon","background","foreground","tooltip","border","selectedText","selectedIcon","selectedBackground","selectedForeground","selectedTooltip","selectedBorder"]

	rows = []
	
	
	home = [u"", u"Accueil", "Builtin/icons/16/home.png", "color(255,255,255,255)", "color(46,46,46,255)", u"Page d'accueil", "", "", "Builtin/icons/16/home.png", "color(71,169,230,255)", "color(255,255,255,255)", "", ""]
	rows.append(home)

	administration = [u"", u"Administration", "Builtin/icons/16/lock.png", "color(255,255,255,255)", "color(46,46,46,255)", u"Administration", "", "", "Builtin/icons/16/lock_open.png", "color(71,169,230,255)", "color(255,255,255,255)", "", ""]
	rows.append(administration)

	astreinte = [u"Administration", u"Astreinte", "Builtin/icons/16/businessmen.png", "color(255,255,255,255)", "color(46,46,46,255)", u"Gestion des groupes d'astreinte" , "", "", "Builtin/icons/16/businessmen.png", "color(71,169,230,255)", "color(255,255,255,255)", "", ""]
	rows.append(astreinte)		
		
	gestionPostes = [u"Administration", u"Postes", "Builtin/icons/16/workstation1.png", "color(255,255,255,255)", "color(46,46,46,255)", u"Gestion des postes", "", "", "Builtin/icons/16/workstation1.png", "color(71,169,230,255)", "color(255,255,255,255)", "", ""]
	rows.append(gestionPostes)	
		
	gestionSignaux = [u"Administration", u"Signaux", "Builtin/icons/16/oszillograph.png", "color(255,255,255,255)", "color(46,46,46,255)", u"Gestion des signaux", "", "", "Builtin/icons/16/oszillograph.png", "color(71,169,230,255)", "color(255,255,255,255)", "", ""]
	rows.append(gestionSignaux)			

[...]

	self.data = system.dataset.toDataSet(headers, rows)