diff --git a/examples/mycontrols/main.cpp b/examples/mycontrols/main.cpp
index 3a764814..996bcd02 100644
--- a/examples/mycontrols/main.cpp
+++ b/examples/mycontrols/main.cpp
@@ -16,6 +16,7 @@
 #include <QskBox.h>
 #include <QskLinearBox.h>
 #include <QskSkinManager.h>
+#include <QskAnimationHint.h>
 #include <QskSkinTransition.h>
 #include <QskSetup.h>
 #include <QskSkin.h>
diff --git a/src/controls/QskSkinTransition.cpp b/src/controls/QskSkinTransition.cpp
index 5e20ca9f..ef3d6ec6 100644
--- a/src/controls/QskSkinTransition.cpp
+++ b/src/controls/QskSkinTransition.cpp
@@ -2,6 +2,7 @@
 #include "QskColorFilter.h"
 #include "QskControl.h"
 #include "QskWindow.h"
+#include "QskAnimationHint.h"
 #include "QskHintAnimator.h"
 #include "QskSkin.h"
 #include "QskSkinHintTable.h"
@@ -518,10 +519,17 @@ namespace
 
 Q_GLOBAL_STATIC( AnimatorGroups, qskSkinAnimator )
 
-QskSkinTransition::QskSkinTransition()
-    : m_mask( QskSkinTransition::AllTypes )
+class QskSkinTransition::PrivateData
+{
+  public:
+    QskSkin* skins[ 2 ] = {};
+    QskAnimationHint animationHint;
+    Type mask = QskSkinTransition::AllTypes;
+};
+
+QskSkinTransition::QskSkinTransition()
+    : m_data( new PrivateData() )
 {
-    m_skins[ 0 ] = m_skins[ 1 ] = nullptr;
 }
 
 QskSkinTransition::~QskSkinTransition()
@@ -530,42 +538,42 @@ QskSkinTransition::~QskSkinTransition()
 
 void QskSkinTransition::setMask( Type type )
 {
-    m_mask = type;
+    m_data->mask = type;
 }
 
 QskSkinTransition::Type QskSkinTransition::mask() const
 {
-    return m_mask;
+    return m_data->mask;
 }
 
 void QskSkinTransition::setSourceSkin( QskSkin* skin )
 {
-    m_skins[ 0 ] = skin;
+    m_data->skins[ 0 ] = skin;
 }
 
 QskSkin* QskSkinTransition::sourceSkin() const
 {
-    return m_skins[ 0 ];
+    return m_data->skins[ 0 ];
 }
 
 void QskSkinTransition::setTargetSkin( QskSkin* skin )
 {
-    m_skins[ 1 ] = skin;
+    m_data->skins[ 1 ] = skin;
 }
 
 QskSkin* QskSkinTransition::targetSkin() const
 {
-    return m_skins[ 1 ];
+    return m_data->skins[ 1 ];
 }
 
 void QskSkinTransition::setAnimation( QskAnimationHint animationHint )
 {
-    m_animationHint = animationHint;
+    m_data->animationHint = animationHint;
 }
 
 QskAnimationHint QskSkinTransition::animation() const
 {
-    return m_animationHint;
+    return m_data->animationHint;
 }
 
 void QskSkinTransition::updateSkin( QskSkin*, QskSkin* )
@@ -575,7 +583,10 @@ void QskSkinTransition::updateSkin( QskSkin*, QskSkin* )
 
 void QskSkinTransition::process()
 {
-    if ( ( m_skins[ 0 ] == nullptr ) || ( m_skins[ 1 ] == nullptr ) )
+    auto skinFrom = m_data->skins[ 0 ];
+    auto skinTo = m_data->skins[ 1 ];
+
+    if ( ( skinFrom == nullptr ) || ( skinTo == nullptr ) )
     {
         // do nothing
         return;
@@ -583,32 +594,32 @@ void QskSkinTransition::process()
 
     qskSkinAnimator->reset();
 
-    if ( ( m_animationHint.duration <= 0 ) || ( m_mask == 0 ) )
+    if ( ( m_data->animationHint.duration <= 0 ) || ( m_data->mask == 0 ) )
     {
         // no animations, we can apply the changes
-        updateSkin( m_skins[ 0 ], m_skins[ 1 ] );
+        updateSkin( skinFrom, skinTo );
         return;
     }
 
     QVector< AnimatorCandidate > candidates;
-    const auto oldFilters = m_skins[ 0 ]->graphicFilters();
+    const auto oldFilters = skinFrom->graphicFilters();
 
     {
         // copy out all hints before updating the skin
         // - would be good to have Copy on Write here
 
-        const auto oldTable = m_skins[ 0 ]->hintTable();
+        const auto oldTable = skinFrom->hintTable();
 
         // apply the changes
-        updateSkin( m_skins[ 0 ], m_skins[ 1 ] );
+        updateSkin( skinFrom, skinTo );
 
-        candidates = qskAnimatorCandidates( m_mask, oldTable, oldFilters,
-            m_skins[ 1 ]->hintTable(), m_skins[ 1 ]->graphicFilters() );
+        candidates = qskAnimatorCandidates( m_data->mask, oldTable, oldFilters,
+            skinTo->hintTable(), skinTo->graphicFilters() );
     }
 
     if ( !candidates.isEmpty() )
     {
-        bool doGraphicFilter = m_mask & QskSkinTransition::Color;
+        bool doGraphicFilter = m_data->mask & QskSkinTransition::Color;
 
         const auto windows = qGuiApp->topLevelWindows();
 
@@ -617,7 +628,7 @@ void QskSkinTransition::process()
             if ( auto quickWindow = qobject_cast< QQuickWindow* >( window ) )
             {
                 if ( !quickWindow->isVisible() ||
-                    ( qskEffectiveSkin( quickWindow ) != m_skins[ 1 ] ) )
+                    ( qskEffectiveSkin( quickWindow ) != skinTo ) )
                 {
                     continue;
                 }
@@ -627,8 +638,8 @@ void QskSkinTransition::process()
                 if ( doGraphicFilter )
                 {
                     group->addGraphicFilterAnimators(
-                        m_animationHint, oldFilters,
-                        m_skins[ 1 ]->graphicFilters() );
+                        m_data->animationHint, oldFilters,
+                        skinTo->graphicFilters() );
 
                     doGraphicFilter = false;
                 }
@@ -639,7 +650,7 @@ void QskSkinTransition::process()
                  */
 
                 group->addAnimators( quickWindow->contentItem(),
-                    m_animationHint, candidates, m_skins[ 1 ] );
+                    m_data->animationHint, candidates, skinTo );
 
                 qskSkinAnimator->add( group );
             }
diff --git a/src/controls/QskSkinTransition.h b/src/controls/QskSkinTransition.h
index 5174569b..6fc13f1b 100644
--- a/src/controls/QskSkinTransition.h
+++ b/src/controls/QskSkinTransition.h
@@ -1,10 +1,11 @@
 #ifndef QSK_SKIN_TRANSITION_H
 #define QSK_SKIN_TRANSITION_H
 
-#include "QskAnimationHint.h"
 #include "QskAspect.h"
+#include <memory>
 
 class QskSkin;
+class QskAnimationHint;
 class QQuickWindow;
 class QVariant;
 
@@ -46,9 +47,8 @@ class QSK_EXPORT QskSkinTransition
   private:
     Q_DISABLE_COPY( QskSkinTransition )
 
-    QskSkin* m_skins[ 2 ];
-    QskAnimationHint m_animationHint;
-    Type m_mask : 2;
+    class PrivateData;
+    std::unique_ptr< PrivateData > m_data;
 };
 
 #endif
diff --git a/support/SkinnyShortcut.cpp b/support/SkinnyShortcut.cpp
index 44a3d423..670405ca 100644
--- a/support/SkinnyShortcut.cpp
+++ b/support/SkinnyShortcut.cpp
@@ -8,6 +8,7 @@
 #include <QskSkin.h>
 #include <QskControl.h>
 #include <QskQuick.h>
+#include <QskAnimationHint.h>
 #include <QskSkinTransition.h>
 
 #include <QQuickItem>