TreeView: Fix a possible crash in ExpandAll().

[GB.GUI.BASE]
* BUG: TreeView: Fix a possible crash in ExpandAll().

comp/src/gb.gui.base/.project

@@ -1,6 +1,6 @@
 # Gambas Project File 3.0
 Title=Common controls and classes for GUI components
-Startup=FTestTreeView
+Startup=FTestLabel
 Icon=.hidden/window.png
 Version=3.18.90
 VersionFile=1

comp/src/gb.gui.base/.src/Test/FTestLabel.form

@@ -2,7 +2,7 @@
 
 { Form Form
   MoveScaled(0,0,103,110)
-  Font = Font["DejaVu Sans,Italic,+5"]
+  Font = Font["DejaVu Sans,Bold"]
   Spacing = True
   { Label4 Label
     MoveScaled(6,13,72,9)
@@ -67,8 +67,8 @@
   }
   { Label9 Label
     MoveScaled(14,3,35,5)
-    Alignment = Align.Center
+    Font = Font["-1"]
     Border = Border.Plain
-    Text = ("Texte")
+    Text = ("Nom du paquet")
   }
 }

comp/src/gb.gui.base/.src/TreeView/_TreeView_Item.class

@@ -730,14 +730,15 @@ Public Sub _ExpandChildren()
   Dim hTree As _TreeView
   Dim sChild As String
   
+  Expanded_Write(True)
   If Not $aChildren Then Return
   
-  Expanded_Write(True)
-  
   hTree = GetTree()
-  For Each sChild In $aChildren
-    hTree[sChild]._ExpandChildren()
-  Next
+  If $aChildren Then
+    For Each sChild In $aChildren
+      hTree[sChild]._ExpandChildren()
+    Next
+  Endif
   
 End