Initialize wxPGChoices object properly in its copy ctor if source object has no data.

Internal data must be always initialized whether the source object contains choices data or not.

Closes #16855

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78484 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -100,6 +100,7 @@ All (GUI):
 - Add wxOwnerDrawnComboBox::Is{List,Text}Empty() methods.
 - Fix creating/removing mode buttons in wxPG manager (Artur Wieczorek).
 - Harmonize wxMenuEvent handling between all major ports.
+- Fix wxPGChoices copy ctor (Snoits).
 
 wxGTK:
 

include/wx/propgrid/property.h

@@ -858,6 +858,10 @@ public:
             m_data = a.m_data;
             m_data->IncRef();
         }
+        else
+        {
+            Init();
+        }
     }
 
     /**