utilities: Fix CheckedStaticBox behaviour

Avoid enabling the child windows when SetValue is called if the window
is currently disabled.

Also continue processing the checkbox event after it has been handled,
which allows the event to propagate to the parent window.

common/src/Utilities/CheckedStaticBox.cpp

@@ -35,6 +35,7 @@ CheckedStaticBox::CheckedStaticBox(wxWindow *parent, int orientation, const wxSt
 void CheckedStaticBox::MainToggle_Click(wxCommandEvent &evt)
 {
     SetValue(evt.IsChecked());
+    evt.Skip();
 }
 
 // Sets the main checkbox status, and enables/disables all child controls
@@ -46,7 +47,7 @@ void CheckedStaticBox::SetValue(bool val)
     for (wxWindowList::iterator iter = list.begin(); iter != list.end(); ++iter) {
         wxWindow *current = *iter;
         if (current != &ThisToggle)
-            current->Enable(val);
+            current->Enable(IsEnabled() && val);
     }
     ThisToggle.SetValue(val);
 }