diff --git a/docs/changes.txt b/docs/changes.txt
index 290420065b..88a119573b 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -90,6 +90,7 @@ All (GUI):
 - Add wxListCtrl::SetHeaderAttr().
 - Add support for using markup in wxDataViewCtrl text items.
 - Implement auto complete in generic wxSearchCtrl (Eric Jensen).
+- Fix preserving selection when changing selection mode in wxGrid (jonkraber).
 
 wxGTK:
 
diff --git a/src/generic/gridsel.cpp b/src/generic/gridsel.cpp
index c6cf59f389..3f0f3f596b 100644
--- a/src/generic/gridsel.cpp
+++ b/src/generic/gridsel.cpp
@@ -144,14 +144,15 @@ void wxGridSelection::SetSelectionMode( wxGrid::wxGridSelectionModes selmode )
         }
 
         // Note that m_blockSelectionTopLeft's size may be changing!
-        for (n = 0; n < m_blockSelectionTopLeft.GetCount(); n++)
+        for ( n = m_blockSelectionTopLeft.GetCount(); n > 0; )
         {
+            n--;
             wxGridCellCoords& coords = m_blockSelectionTopLeft[n];
             int topRow = coords.GetRow();
             int leftCol = coords.GetCol();
-            coords = m_blockSelectionBottomRight[n];
-            int bottomRow = coords.GetRow();
-            int rightCol = coords.GetCol();
+            wxGridCellCoords& coords2 = m_blockSelectionBottomRight[n];
+            int bottomRow = coords2.GetRow();
+            int rightCol = coords2.GetCol();
 
             if (selmode == wxGrid::wxGridSelectRows)
             {