wpf - Binding view with model (view doesn't update) -

I am implementing something, that if I select something in my list box, some text boxes are visible so I select I can fill some details of the item I have already applied a visibility converter and this is my code xaml and viewodal:

There are questions about the item class in the list box

  Public questions selected Q & A drop list {Get {return selectedQuestionDrop; } Set {selectedQuestionDrop = value; OnPropertyChanged ("SelectedQuestionDropList"); Visible = true; }}   
 This is my visibility property:  
  Public Boolean Visible {Get {return view; } Set {visible = value; }}   
 My xaml looks like this:  
  & lt; List box selected item = "{binding path = selected question control, updateunderstraggers = changing property, mode = two}" DisplayMemberPath = "description" /> & Lt; Text box height = "23" visibility = "{binding path = visible, converter = {static resource balltovis}, updates resource resetter = property changes, mode}" />   
 But I have a problem, when I choose something, the property visible is set to true, but the visibility of the text box remains false .. So my visual view modal Is not updated with Anyone who knows what I'm doing is wrong?   
 
 
 To change the visibility binding you must change your property to OnPropertyChanged:  
  public boolean visible {received {return view; } Set {visible = value; OnPropertyChanged ("Viewable"); }}