Bugs with addGUIElement

Type TGUI
    Field element:IGUIElement, element_name:String
    Field button:IGUIButton[16] , checkbox:IGUICheckBox[16] , colorselectdialog:IGUIColorSelectDialog
    Field combobox:IGUIComboBox[4] , contextmenu:IGUIContextMenu[2] , editbox:IGUIEditBox[16] 
    Field fileopendialog:IGUIFileOpenDialog, image:IGUIImage[32] , inoutfader:IGUIInOutFader[4] 
    Field listbox:IGUIListBox[4] , meshviewer:IGUIMeshViewer[2] , scrollbar:IGUIScrollBar[4] 
    Field statictext:IGUIStaticText[32] , tab:IGUITab[4] , tabcontrol:IGUITabControl[4] 
    Field toolbar:IGUIToolBar[2] , iwindow:IGUIWindow[2] 
EndType
Global TGUI_list:TList = New TList

Function Generate_GUI(file_url:String, name_element:String) 
    Local button_var:Int

    Local gui:TGUI = New TGUI
    TGUI_list.AddLast gui
    
    gui.element_name = name_element:String
    gui.element = env.addGUIElement(gui.element_name) 
    If gui.element = Null
    DebugLog gui.element_name + " ^ Null"
    EndIf
    gui.element.setMinSize(_DIMENSION2DI(app_vars:Int[graphics_width] , app_vars:Int[graphics_height] )) 
    
    Local xml:TXml = New TXml
    TXml_list.Addlast xml
    xml.file:IXMLReaderUTF8 = current_filesystem.createXMLReaderUTF8(file_url:String) 
    While xml.file.read() 
        Select xml.file.getNodeType() 
            Case EXN_ELEMENT
                Select xml.file.getNodeName() 
                    Case "gui"
                        Select xml.file.getAttributeValue("type_gui") 
                            Case "button"
                                button_var:+1
                                gui.button[button_var] = env.addButton(_RECTI(Int(xml.file.getAttributeValue("x1")), Int(xml.file.getAttributeValue("y1")), Int(xml.file.getAttributeValue("x2")), Int(xml.file.getAttributeValue("y2"))), gui.element, Int(xml.file.getAttributeValue("id")), xml.file.getAttributeValue("text"), xml.file.getAttributeValue("tooltip")) 
                                DebugLog "button"
                            Default
                        endselect
                        xml.nodename:String = xml.file.getNodeName() 
                End Select
            Case EXN_TEXT
                Select xml.nodename:String
                    Case "gui"
                        DebugLog xml.file.getNodeData() 
                End Select 
        End Select
    Wend
    TXml_list.remove(xml) 
EndFunction

gui.element.setMinSize(_DIMENSION2DI(app_vars:Int[graphics_width] , app_vars:Int[graphics_height] ))