Support NULL column in wxDataViewCtrl::GetItemRect() in wxOSX

Emulate support for non-specified column by using the first and, if
necessary, last columns in this case.

interface/wx/dataview.h

@@ -1462,9 +1462,7 @@ public:
             intersection of the item with the specified column. If @NULL, the
             rectangle spans all the columns.
 
-        @note This method is currently not implemented at all in wxGTK and only
+        @note This method is currently not implemented in wxGTK.
-              implemented for non-@NULL @a col argument in wxOSX. It is fully
-              implemented in the generic version of the control.
     */
     virtual wxRect GetItemRect(const wxDataViewItem& item,
                                const wxDataViewColumn* col = NULL) const;

src/osx/dataview_osx.cpp

@@ -547,10 +547,24 @@ wxDataViewColumn *wxDataViewCtrl::GetCurrentColumn() const
 
 wxRect wxDataViewCtrl::GetItemRect(wxDataViewItem const& item, wxDataViewColumn const* columnPtr) const
 {
-  if (item.IsOk() && (columnPtr != NULL))
+  if ( !item.IsOk() )
-    return GetDataViewPeer()->GetRectangle(item,columnPtr);
+      return wxRect();
-  else
+
-    return wxRect();
+  wxRect rect = GetDataViewPeer()->GetRectangle(item, columnPtr ? columnPtr : GetColumn(0));
+
+  if ( !columnPtr )
+  {
+      const unsigned columnCount = GetColumnCount();
+      if ( columnCount != 1 )
+      {
+          // Extend the rectangle to the rightmost part of the last column.
+          const wxRect rectLastCol = GetDataViewPeer()->GetRectangle(item, GetColumn(columnCount - 1));
+          rect.SetRight(rectLastCol.GetRight());
+      }
+      //else: We already have the rectangle we need.
+  }
+
+  return rect;
 }
 
 int wxDataViewCtrl::GetSelectedItemsCount() const