diff --git a/include/wx/generic/private/grid.h b/include/wx/generic/private/grid.h
index c67f462902..d0c01a16af 100644
--- a/include/wx/generic/private/grid.h
+++ b/include/wx/generic/private/grid.h
@@ -1007,5 +1007,12 @@ private:
     wxGridDataTypeInfoArray m_typeinfo;
 };
 
+// Returns the rect of the check box in a cell with the given alignmens
+// and the size.
+// The function is used by wxGridCellBoolEditor and wxGridCellBoolRenderer.
+wxRect wxGetGridCheckBoxRect(const wxSize& checkBoxSize,
+                             const wxRect& cellRect,
+                             int hAlign, int vAlign);
+
 #endif // wxUSE_GRID
 #endif // _WX_GENERIC_GRID_PRIVATE_H_
diff --git a/src/generic/grid.cpp b/src/generic/grid.cpp
index f940fbbd40..2648f750a9 100644
--- a/src/generic/grid.cpp
+++ b/src/generic/grid.cpp
@@ -111,6 +111,9 @@ const int GRID_HASH_SIZE = 100;
 // operation
 const int DRAG_SENSITIVITY = 3;
 
+// the space between the cell edge and the checkbox mark
+const int GRID_CELL_CHECKBOX_MARGIN_X = 2;
+
 } // anonymous namespace
 
 #include "wx/arrimpl.cpp"
@@ -6980,18 +6983,10 @@ void wxGrid::ShowCellEditControl()
             if (rect.x < 0)
                 nXMove = rect.x;
 
-#ifndef __WXQT__
-            // cell is shifted by one pixel
-            // However, don't allow x or y to become negative
-            // since the SetSize() method interprets that as
-            // "don't change."
-            if (rect.x > 0)
-                rect.x--;
-            if (rect.y > 0)
-                rect.y--;
-#else
+#ifdef __WXQT__
             // Substract 1 pixel in every dimension to fit in the cell area.
             // If not, Qt will draw the control outside the cell.
+            // TODO: Check offsets under Qt.
             rect.Deflate(1, 1);
 #endif
 
@@ -10337,4 +10332,44 @@ wxGridCellEditor* wxGridTypeRegistry::GetEditor(int index)
     return editor;
 }
 
+wxRect wxGetGridCheckBoxRect(const wxSize& checkBoxSize,
+                             const wxRect& cellRect,
+                             int hAlign, int WXUNUSED(vAlign))
+{
+    // TODO: support vAlign
+
+    wxRect checkBoxRect;
+    checkBoxRect.SetY(cellRect.y + cellRect.height / 2 - checkBoxSize.y / 2);
+
+    wxCoord minSize = wxMin(cellRect.width, cellRect.height);
+    if ( checkBoxRect.GetWidth() >= minSize || checkBoxRect.GetHeight() >= minSize )
+    {
+        // let the checkbox mark be even smaller than the min size
+        // to leave some space between cell edges and the checkbox
+        const int newSize = wxMax(1, minSize - 2);
+        checkBoxRect.SetWidth(newSize);
+        checkBoxRect.SetHeight(newSize);
+    }
+    else
+    {
+        checkBoxRect.SetSize(checkBoxSize);
+    }
+
+    if ( hAlign & wxALIGN_CENTER_HORIZONTAL )
+    {
+        checkBoxRect.SetX(cellRect.x + cellRect.width / 2 - checkBoxSize.x / 2);
+    }
+    else if ( hAlign & wxALIGN_RIGHT )
+    {
+        checkBoxRect.SetX(cellRect.x + cellRect.width
+                          - checkBoxSize.x - GRID_CELL_CHECKBOX_MARGIN_X);
+    }
+    else // ( hAlign == wxALIGN_LEFT ) and invalid alignment value
+    {
+        checkBoxRect.SetX(cellRect.x + GRID_CELL_CHECKBOX_MARGIN_X);
+    }
+
+    return checkBoxRect;
+}
+
 #endif // wxUSE_GRID
diff --git a/src/generic/gridctrl.cpp b/src/generic/gridctrl.cpp
index f6df548502..a72c4b1674 100644
--- a/src/generic/gridctrl.cpp
+++ b/src/generic/gridctrl.cpp
@@ -31,6 +31,7 @@
 #include "wx/tokenzr.h"
 #include "wx/renderer.h"
 
+#include "wx/generic/private/grid.h"
 
 // ----------------------------------------------------------------------------
 // wxGridCellRenderer
@@ -936,7 +937,8 @@ wxSize wxGridCellBoolRenderer::GetBestSize(wxGrid& grid,
     // compute it only once (no locks for MT safeness in GUI thread...)
     if ( !ms_sizeCheckMark.x )
     {
-        ms_sizeCheckMark = wxRendererNative::Get().GetCheckBoxSize(&grid);
+        ms_sizeCheckMark =
+            wxRendererNative::Get().GetCheckBoxSize(&grid, wxCONTROL_CELL);
     }
 
     return ms_sizeCheckMark;
@@ -951,43 +953,16 @@ void wxGridCellBoolRenderer::Draw(wxGrid& grid,
 {
     wxGridCellRenderer::Draw(grid, attr, dc, rect, row, col, isSelected);
 
-    // draw a check mark in the centre (ignoring alignment - TODO)
-    wxSize size = GetBestSize(grid, attr, dc, row, col);
-
-    // don't draw outside the cell
-    wxCoord minSize = wxMin(rect.width, rect.height);
-    if ( size.x >= minSize || size.y >= minSize )
-    {
-        // and even leave (at least) 1 pixel margin
-        size.x = size.y = minSize;
-    }
-
-    // draw a border around checkmark
     int vAlign, hAlign;
     attr.GetAlignment(&hAlign, &vAlign);
 
-    wxRect rectBorder;
-    if (hAlign == wxALIGN_CENTRE)
-    {
-        rectBorder.x = rect.x + rect.width / 2 - size.x / 2;
-        rectBorder.y = rect.y + rect.height / 2 - size.y / 2;
-        rectBorder.width = size.x;
-        rectBorder.height = size.y;
-    }
-    else if (hAlign == wxALIGN_LEFT)
-    {
-        rectBorder.x = rect.x + 2;
-        rectBorder.y = rect.y + rect.height / 2 - size.y / 2;
-        rectBorder.width = size.x;
-        rectBorder.height = size.y;
-    }
-    else if (hAlign == wxALIGN_RIGHT)
-    {
-        rectBorder.x = rect.x + rect.width - size.x - 2;
-        rectBorder.y = rect.y + rect.height / 2 - size.y / 2;
-        rectBorder.width = size.x;
-        rectBorder.height = size.y;
-    }
+    const wxRect
+        checkBoxRect = wxGetGridCheckBoxRect
+                       (
+                            GetBestSize(grid, attr, dc, row, col),
+                            rect,
+                            hAlign, vAlign
+                        );
 
     bool value;
     if ( grid.GetTable()->CanGetValueAs(row, col, wxGRID_VALUE_BOOL) )
@@ -1000,11 +975,11 @@ void wxGridCellBoolRenderer::Draw(wxGrid& grid,
         value = wxGridCellBoolEditor::IsTrueValue(cellval);
     }
 
-    int flags = 0;
+    int flags = wxCONTROL_CELL;
     if (value)
         flags |= wxCONTROL_CHECKED;
 
-    wxRendererNative::Get().DrawCheckBox( &grid, dc, rectBorder, flags );
+    wxRendererNative::Get().DrawCheckBox( &grid, dc, checkBoxRect, flags );
 }
 
 #endif // wxUSE_GRID
diff --git a/src/generic/grideditors.cpp b/src/generic/grideditors.cpp
index e5b008697b..08954cc7fe 100644
--- a/src/generic/grideditors.cpp
+++ b/src/generic/grideditors.cpp
@@ -440,38 +440,17 @@ void wxGridCellTextEditor::SetSize(const wxRect& rectOrig)
 
     // Make the edit control large enough to allow for internal margins
     //
-    // TODO: remove this if the text ctrl sizing is improved esp. for unix
+    // TODO: remove this if the text ctrl sizing is improved
     //
-#if defined(__WXGTK__)
-    if (rect.x != 0)
-    {
-        rect.x += 1;
-        rect.y += 1;
-        rect.width -= 1;
-        rect.height -= 1;
-    }
-#elif defined(__WXMSW__)
-    if ( rect.x == 0 )
-        rect.x += 2;
-    else
-        rect.x += 3;
-
-    if ( rect.y == 0 )
-        rect.y += 2;
-    else
-        rect.y += 3;
+#if defined(__WXMSW__)
+    rect.x += 2;
+    rect.y += 2;
 
     rect.width -= 2;
     rect.height -= 2;
-#elif defined(__WXOSX__)
-    rect.x += 1;
-    rect.y += 1;
-    
-    rect.width -= 1;
-    rect.height -= 1;
-#else
-    int extra_x = ( rect.x > 2 ) ? 2 : 1;
-    int extra_y = ( rect.y > 2 ) ? 2 : 1;
+#elif !defined(__WXGTK__)
+    int extra_x = 2;
+    int extra_y = 2;
 
     #if defined(__WXMOTIF__)
         extra_x *= 2;
@@ -1239,73 +1218,28 @@ void wxGridCellBoolEditor::Create(wxWindow* parent,
 
 void wxGridCellBoolEditor::SetSize(const wxRect& r)
 {
-    bool resize = false;
-    wxSize size = m_control->GetSize();
-    wxCoord minSize = wxMin(r.width, r.height);
-
-    // check if the checkbox is not too big/small for this cell
-    wxSize sizeBest = m_control->GetBestSize();
-    if ( !(size == sizeBest) )
-    {
-        // reset to default size if it had been made smaller
-        size = sizeBest;
-
-        resize = true;
-    }
-
-    if ( size.x >= minSize || size.y >= minSize )
-    {
-        // leave 1 pixel margin
-        size.x = size.y = minSize - 2;
-
-        resize = true;
-    }
-
-    if ( resize )
-    {
-        m_control->SetSize(size);
-    }
-
-    // position it in the centre of the rectangle (TODO: support alignment?)
-
-#if defined(__WXGTK__) || defined (__WXMOTIF__)
-    // the checkbox without label still has some space to the right in wxGTK,
-    // so shift it to the right
-    size.x -= 8;
-#elif defined(__WXMSW__)
-    // here too, but in other way
-    size.x += 1;
-    size.y -= 2;
-#endif
-
     int hAlign = wxALIGN_CENTRE;
     int vAlign = wxALIGN_CENTRE;
     if (GetCellAttr())
         GetCellAttr()->GetAlignment(& hAlign, & vAlign);
 
-    int x = 0, y = 0;
-    if (hAlign == wxALIGN_LEFT)
-    {
-        x = r.x + 2;
+    const wxRect
+        checkBoxRect = wxGetGridCheckBoxRect
+                       (
+                            wxRendererNative::Get().
+                                GetCheckBoxSize(GetWindow(), wxCONTROL_CELL),
+                            r,
+                            hAlign, vAlign
+                       );
 
-#ifdef __WXMSW__
-        x += 2;
-#endif
-
-        y = r.y + r.height / 2 - size.y / 2;
-    }
-    else if (hAlign == wxALIGN_RIGHT)
+    // resize the control if required
+    if ( m_control->GetSize() != checkBoxRect.GetSize() )
     {
-        x = r.x + r.width - size.x - 2;
-        y = r.y + r.height / 2 - size.y / 2;
-    }
-    else if (hAlign == wxALIGN_CENTRE)
-    {
-        x = r.x + r.width / 2 - size.x / 2;
-        y = r.y + r.height / 2 - size.y / 2;
+        m_control->SetSize(checkBoxRect.GetSize());
     }
 
-    m_control->Move(x, y);
+    // and move it
+    m_control->Move(checkBoxRect.GetPosition());
 }
 
 void wxGridCellBoolEditor::Show(bool show, wxGridCellAttr *attr)