diff --git a/common/widgets/bitmap_button.cpp b/common/widgets/bitmap_button.cpp
index 367d04e1ce..2b3aad5a54 100644
--- a/common/widgets/bitmap_button.cpp
+++ b/common/widgets/bitmap_button.cpp
@@ -92,15 +92,29 @@ BITMAP_BUTTON::~BITMAP_BUTTON()
 
 wxSize BITMAP_BUTTON::DoGetBestSize() const
 {
+    if( hasFlag( wxCONTROL_SEPARATOR ) )
+        return wxSize( m_unadjustedMinSize.x + m_padding * 2, wxButton::GetDefaultSize().y );
+
     return m_unadjustedMinSize + wxSize( m_padding * 2, m_padding * 2 );
 }
 
 
+void BITMAP_BUTTON::invalidateBestSize()
+{
+#ifdef __WXMAC__
+    // InvalidateBestSize() doesn't appear to work on Mac: DoGetBestSize() is never called.
+    SetMinSize( DoGetBestSize() );
+#else
+    InvalidateBestSize();
+#endif
+}
+
+
 void BITMAP_BUTTON::SetPadding( int aPadding )
 {
     m_padding = aPadding;
 
-    InvalidateBestSize();
+    invalidateBestSize();
 }
 
 
@@ -123,7 +137,7 @@ void BITMAP_BUTTON::SetBitmap( const wxBitmapBundle& aBmp )
 #endif
     }
 
-    InvalidateBestSize();
+    invalidateBestSize();
 }
 
 
@@ -261,7 +275,7 @@ void BITMAP_BUTTON::OnDPIChanged( wxDPIChangedEvent& aEvent )
     if( newBmSize != m_unadjustedMinSize )
     {
         m_unadjustedMinSize = newBmSize;
-        InvalidateBestSize();
+        invalidateBestSize();
     }
 
     aEvent.Skip();
@@ -414,7 +428,7 @@ void BITMAP_BUTTON::SetIsSeparator()
 {
     setFlag( wxCONTROL_SEPARATOR | wxCONTROL_DISABLED );
 
-    InvalidateBestSize();
+    invalidateBestSize();
 }
 
 
diff --git a/common/widgets/color_swatch.cpp b/common/widgets/color_swatch.cpp
index 172e724379..96656171e9 100644
--- a/common/widgets/color_swatch.cpp
+++ b/common/widgets/color_swatch.cpp
@@ -21,6 +21,7 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  */
 
+#include <kiplatform/ui.h>
 #include <widgets/color_swatch.h>
 #include <wx/dcmemory.h>
 
@@ -146,6 +147,12 @@ COLOR_SWATCH::COLOR_SWATCH( wxWindow* aParent, const COLOR4D& aColor, int aID,
     m_checkerboardSize = ConvertDialogToPixels( CHECKERBOARD_SIZE_DU );
     m_checkerboardBg = aParent->GetBackgroundColour();
 
+#ifdef __WXMAC__
+    // Adjust for Retina
+    m_size *= KIPLATFORM::UI::GetPixelScaleFactor( aParent );
+    m_checkerboardSize *= KIPLATFORM::UI::GetPixelScaleFactor( aParent );
+#endif
+
     auto sizer = new wxBoxSizer( wxHORIZONTAL );
     SetSizer( sizer );
 
@@ -176,6 +183,16 @@ COLOR_SWATCH::COLOR_SWATCH( wxWindow* aParent, wxWindowID aID, const wxPoint& aP
     m_checkerboardSize = ConvertDialogToPixels( CHECKERBOARD_SIZE_DU );
     m_checkerboardBg = aParent->GetBackgroundColour();
 
+#ifdef __WXMAC__
+    // Adjust for border
+    m_size.x -= 2;
+    m_size.y -= 2;
+
+    // Adjust for Retina
+    m_size *= KIPLATFORM::UI::GetPixelScaleFactor( aParent );
+    m_checkerboardSize *= KIPLATFORM::UI::GetPixelScaleFactor( aParent );
+#endif
+
     SetSize( m_size );
 
     auto sizer = new wxBoxSizer( wxHORIZONTAL );
diff --git a/include/widgets/bitmap_button.h b/include/widgets/bitmap_button.h
index 013ec60cd1..4604482f6e 100644
--- a/include/widgets/bitmap_button.h
+++ b/include/widgets/bitmap_button.h
@@ -153,6 +153,8 @@ protected:
         return m_buttonState & aFlag;
     }
 
+    void invalidateBestSize();
+
 private:
     wxBitmapBundle m_normalBitmap;
     wxBitmapBundle m_disabledBitmap;