Adapted the fancy tree to the new container

TermTk/TTkWidgets/Fancy/treewidget.py

@@ -27,6 +27,7 @@ from TermTk.TTkCore.log import TTkLog
 from TermTk.TTkCore.string import TTkString
 from TermTk.TTkCore.signal import pyTTkSlot, pyTTkSignal
 from TermTk.TTkWidgets.widget import TTkWidget
+from TermTk.TTkWidgets.container import TTkContainer
 from TermTk.TTkWidgets.checkbox import TTkCheckbox
 from TermTk.TTkWidgets.Fancy.tableview import TTkFancyTableView
 from TermTk.TTkWidgets.Fancy.treewidgetitem import TTkFancyTreeWidgetItem
@@ -43,7 +44,7 @@ class _TTkDisplayedTreeItemControl(TTkCheckbox):
             canvas.drawText(pos=(0,0), text="▶")
 
 
-class _TTkDisplayedTreeItem(TTkWidget):
+class _TTkDisplayedTreeItem(TTkContainer):
     __slots__ = ('_depth', '_control', '_text', '_id', '_clicked', '_treeWidgetItem', '_isLeaf' )
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)