diff --git a/include/wx/generic/grid.h b/include/wx/generic/grid.h
index 01a02393b3..c81e3fc9dd 100644
--- a/include/wx/generic/grid.h
+++ b/include/wx/generic/grid.h
@@ -1131,6 +1131,8 @@ public:
                          const wxArrayString& lines,
                          long *width, long *height ) const;
 
+    // If bottomRight is invalid, i.e. == wxGridNoCellCoords, it defaults to
+    // topLeft. If topLeft itself is invalid, the function simply returns.
     void RefreshBlock(const wxGridCellCoords& topLeft,
                       const wxGridCellCoords& bottomRight);
 
@@ -1522,6 +1524,8 @@ public:
     // reverse mapping currently
     int GetColPos(int idx) const
     {
+        wxASSERT_MSG( idx >= 0 && idx < m_numCols, "invalid column index" );
+
         if ( m_colAt.IsEmpty() )
             return idx;
 
diff --git a/src/generic/grid.cpp b/src/generic/grid.cpp
index b7f7f387d6..3b2b8cfbe7 100644
--- a/src/generic/grid.cpp
+++ b/src/generic/grid.cpp
@@ -5277,6 +5277,33 @@ void wxGrid::RefreshBlock(const wxGridCellCoords& topLeft,
 void wxGrid::RefreshBlock(int topRow, int leftCol,
                           int bottomRow, int rightCol)
 {
+    // Note that it is valid to call this function with wxGridNoCellCoords as
+    // either or even both arguments, but we can't have a mix of valid and
+    // invalid columns/rows for each corner coordinates.
+    const bool noTopLeft = topRow == -1 || leftCol == -1;
+    const bool noBottomRight = bottomRow == -1 || rightCol == -1;
+
+    if ( noTopLeft )
+    {
+        // So check that either both or none of the components are valid.
+        wxASSERT( topRow == -1 && leftCol == -1 );
+
+        // And specifying bottom right corner when the top left one is not
+        // specified doesn't make sense neither.
+        wxASSERT( noBottomRight );
+
+        return;
+    }
+
+    if ( noBottomRight )
+    {
+        wxASSERT( bottomRow == -1 && rightCol == -1 );
+
+        bottomRow = topRow;
+        rightCol = leftCol;
+    }
+
+
     int row = topRow;
     int col = leftCol;
 
diff --git a/tests/controls/gridtest.cpp b/tests/controls/gridtest.cpp
index 62f9a3d729..76912fc499 100644
--- a/tests/controls/gridtest.cpp
+++ b/tests/controls/gridtest.cpp
@@ -49,6 +49,7 @@ private:
     CPPUNIT_TEST_SUITE( GridTestCase );
         WXUISIM_TEST( CellEdit );
         NONGTK_TEST( CellClick );
+        NONGTK_TEST( ReorderedColumnsCellClick );
         NONGTK_TEST( CellSelect );
         NONGTK_TEST( LabelClick );
         NONGTK_TEST( SortClick );
@@ -83,6 +84,7 @@ private:
 
     void CellEdit();
     void CellClick();
+    void ReorderedColumnsCellClick();
     void CellSelect();
     void LabelClick();
     void SortClick();
@@ -232,6 +234,35 @@ void GridTestCase::CellClick()
 #endif
 }
 
+void GridTestCase::ReorderedColumnsCellClick()
+{
+#if wxUSE_UIACTIONSIMULATOR
+    EventCounter click(m_grid, wxEVT_GRID_CELL_LEFT_CLICK);
+
+    wxUIActionSimulator sim;
+
+    wxArrayInt neworder;
+    neworder.push_back(1);
+    neworder.push_back(0);
+
+    m_grid->SetColumnsOrder(neworder);
+
+    wxRect rect = m_grid->CellToRect(0, 1);
+    wxPoint point = m_grid->CalcScrolledPosition(rect.GetPosition());
+    point = m_grid->ClientToScreen(point + wxPoint(m_grid->GetRowLabelSize(),
+        m_grid->GetColLabelSize())
+        + wxPoint(2, 2));
+
+    sim.MouseMove(point);
+    wxYield();
+
+    sim.MouseClick();
+    wxYield();
+
+    CPPUNIT_ASSERT_EQUAL(1, click.GetCount());
+#endif
+}
+
 void GridTestCase::CellSelect()
 {
 #if wxUSE_UIACTIONSIMULATOR