diff --git a/kdecoration/breezebutton.cpp b/kdecoration/breezebutton.cpp
--- a/kdecoration/breezebutton.cpp
+++ b/kdecoration/breezebutton.cpp
@@ -55,7 +55,7 @@
         setIconSize(QSize( height, height ));
 
         // connections
-        connect(decoration->client().data(), SIGNAL(iconChanged(QIcon)), this, SLOT(update()));
+        connect(decoration->client().toStrongRef().data(), SIGNAL(iconChanged(QIcon)), this, SLOT(update()));
         connect(decoration->settings().data(), &KDecoration2::DecorationSettings::reconfigured, this, &Button::reconfigure);
         connect( this, &KDecoration2::DecorationButton::hoveredChanged, this, &Button::updateAnimationState );
 
@@ -83,32 +83,32 @@
             {
 
                 case DecorationButtonType::Close:
-                b->setVisible( d->client().data()->isCloseable() );
-                QObject::connect(d->client().data(), &KDecoration2::DecoratedClient::closeableChanged, b, &Breeze::Button::setVisible );
+                b->setVisible( d->client().toStrongRef().data()->isCloseable() );
+                QObject::connect(d->client().toStrongRef().data(), &KDecoration2::DecoratedClient::closeableChanged, b, &Breeze::Button::setVisible );
                 break;
 
                 case DecorationButtonType::Maximize:
-                b->setVisible( d->client().data()->isMaximizeable() );
-                QObject::connect(d->client().data(), &KDecoration2::DecoratedClient::maximizeableChanged, b, &Breeze::Button::setVisible );
+                b->setVisible( d->client().toStrongRef().data()->isMaximizeable() );
+                QObject::connect(d->client().toStrongRef().data(), &KDecoration2::DecoratedClient::maximizeableChanged, b, &Breeze::Button::setVisible );
                 break;
 
                 case DecorationButtonType::Minimize:
-                b->setVisible( d->client().data()->isMinimizeable() );
-                QObject::connect(d->client().data(), &KDecoration2::DecoratedClient::minimizeableChanged, b, &Breeze::Button::setVisible );
+                b->setVisible( d->client().toStrongRef().data()->isMinimizeable() );
+                QObject::connect(d->client().toStrongRef().data(), &KDecoration2::DecoratedClient::minimizeableChanged, b, &Breeze::Button::setVisible );
                 break;
 
                 case DecorationButtonType::ContextHelp:
-                b->setVisible( d->client().data()->providesContextHelp() );
-                QObject::connect(d->client().data(), &KDecoration2::DecoratedClient::providesContextHelpChanged, b, &Breeze::Button::setVisible );
+                b->setVisible( d->client().toStrongRef().data()->providesContextHelp() );
+                QObject::connect(d->client().toStrongRef().data(), &KDecoration2::DecoratedClient::providesContextHelpChanged, b, &Breeze::Button::setVisible );
                 break;
 
                 case DecorationButtonType::Shade:
-                b->setVisible( d->client().data()->isShadeable() );
-                QObject::connect(d->client().data(), &KDecoration2::DecoratedClient::shadeableChanged, b, &Breeze::Button::setVisible );
+                b->setVisible( d->client().toStrongRef().data()->isShadeable() );
+                QObject::connect(d->client().toStrongRef().data(), &KDecoration2::DecoratedClient::shadeableChanged, b, &Breeze::Button::setVisible );
                 break;
 
                 case DecorationButtonType::Menu:
-                QObject::connect(d->client().data(), &KDecoration2::DecoratedClient::iconChanged, b, [b]() { b->update(); });
+                QObject::connect(d->client().toStrongRef().data(), &KDecoration2::DecoratedClient::iconChanged, b, [b]() { b->update(); });
                 break;
 
                 default: break;
@@ -142,7 +142,7 @@
         {
 
             const QRectF iconRect( geometry().topLeft(), m_iconSize );
-            decoration()->client().data()->icon().paint(painter, iconRect.toRect());
+            decoration()->client().toStrongRef().data()->icon().paint(painter, iconRect.toRect());
 
 
         } else {
@@ -404,7 +404,7 @@
 
         }
 
-        auto c = d->client().data();
+        auto c = d->client().toStrongRef().data();
         if( isPressed() ) {
 
             if( type() == DecorationButtonType::Close ) return c->color( ColorGroup::Warning, ColorRole::Foreground );
diff --git a/kdecoration/breezedecoration.h b/kdecoration/breezedecoration.h
--- a/kdecoration/breezedecoration.h
+++ b/kdecoration/breezedecoration.h
@@ -169,28 +169,28 @@
     }
 
     bool Decoration::isMaximized() const
-    { return client().data()->isMaximized() && !m_internalSettings->drawBorderOnMaximizedWindows(); }
+    { return client().toStrongRef().data()->isMaximized() && !m_internalSettings->drawBorderOnMaximizedWindows(); }
 
     bool Decoration::isMaximizedHorizontally() const
-    { return client().data()->isMaximizedHorizontally() && !m_internalSettings->drawBorderOnMaximizedWindows(); }
+    { return client().toStrongRef().data()->isMaximizedHorizontally() && !m_internalSettings->drawBorderOnMaximizedWindows(); }
 
     bool Decoration::isMaximizedVertically() const
-    { return client().data()->isMaximizedVertically() && !m_internalSettings->drawBorderOnMaximizedWindows(); }
+    { return client().toStrongRef().data()->isMaximizedVertically() && !m_internalSettings->drawBorderOnMaximizedWindows(); }
 
     bool Decoration::isLeftEdge() const
-    { return (client().data()->isMaximizedHorizontally() || client().data()->adjacentScreenEdges().testFlag( Qt::LeftEdge ) ) && !m_internalSettings->drawBorderOnMaximizedWindows(); }
+    { return (client().toStrongRef().data()->isMaximizedHorizontally() || client().toStrongRef().data()->adjacentScreenEdges().testFlag( Qt::LeftEdge ) ) && !m_internalSettings->drawBorderOnMaximizedWindows(); }
 
     bool Decoration::isRightEdge() const
-    { return (client().data()->isMaximizedHorizontally() || client().data()->adjacentScreenEdges().testFlag( Qt::RightEdge ) ) && !m_internalSettings->drawBorderOnMaximizedWindows(); }
+    { return (client().toStrongRef().data()->isMaximizedHorizontally() || client().toStrongRef().data()->adjacentScreenEdges().testFlag( Qt::RightEdge ) ) && !m_internalSettings->drawBorderOnMaximizedWindows(); }
 
     bool Decoration::isTopEdge() const
-    { return (client().data()->isMaximizedVertically() || client().data()->adjacentScreenEdges().testFlag( Qt::TopEdge ) ) && !m_internalSettings->drawBorderOnMaximizedWindows(); }
+    { return (client().toStrongRef().data()->isMaximizedVertically() || client().toStrongRef().data()->adjacentScreenEdges().testFlag( Qt::TopEdge ) ) && !m_internalSettings->drawBorderOnMaximizedWindows(); }
 
     bool Decoration::isBottomEdge() const
-    { return (client().data()->isMaximizedVertically() || client().data()->adjacentScreenEdges().testFlag( Qt::BottomEdge ) ) && !m_internalSettings->drawBorderOnMaximizedWindows(); }
+    { return (client().toStrongRef().data()->isMaximizedVertically() || client().toStrongRef().data()->adjacentScreenEdges().testFlag( Qt::BottomEdge ) ) && !m_internalSettings->drawBorderOnMaximizedWindows(); }
 
     bool Decoration::hideTitleBar() const
-    { return m_internalSettings->hideTitleBar() && !client().data()->isShaded(); }
+    { return m_internalSettings->hideTitleBar() && !client().toStrongRef().data()->isShaded(); }
 
 }
 
diff --git a/kdecoration/breezedecoration.cpp b/kdecoration/breezedecoration.cpp
--- a/kdecoration/breezedecoration.cpp
+++ b/kdecoration/breezedecoration.cpp
@@ -192,7 +192,7 @@
     QColor Decoration::titleBarColor() const
     {
 
-        auto c = client().data();
+        auto c = client().toStrongRef().data();
         if( hideTitleBar() ) return c->color( ColorGroup::Inactive, ColorRole::TitleBar );
         else if( m_animation->state() == QAbstractAnimation::Running )
         {
@@ -208,7 +208,7 @@
     QColor Decoration::outlineColor() const
     {
 
-        auto c( client().data() );
+        auto c( client().toStrongRef().data() );
         if( !m_internalSettings->drawTitleBarSeparator() ) return QColor();
         if( m_animation->state() == QAbstractAnimation::Running )
         {
@@ -223,7 +223,7 @@
     QColor Decoration::fontColor() const
     {
 
-        auto c = client().data();
+        auto c = client().toStrongRef().data();
         if( m_animation->state() == QAbstractAnimation::Running )
         {
             return KColorUtils::mix(
@@ -237,7 +237,7 @@
     //________________________________________________________________
     void Decoration::init()
     {
-        auto c = client().data();
+        auto c = client().toStrongRef().data();
 
         // active state change animation
         // It is important start and end value are of the same type, hence 0.0 and not just 0
@@ -297,7 +297,7 @@
     void Decoration::updateTitleBar()
     {
         auto s = settings();
-        auto c = client().data();
+        auto c = client().toStrongRef().data();
         const bool maximized = isMaximized();
         const int width =  maximized ? c->width() : c->width() - 2*s->largeSpacing()*Metrics::TitleBar_SideMargin;
         const int height = maximized ? borderTop() : borderTop() - s->smallSpacing()*Metrics::TitleBar_TopMargin;
@@ -312,7 +312,7 @@
         if( m_internalSettings->animationsEnabled() )
         {
 
-            auto c = client().data();
+            auto c = client().toStrongRef().data();
             m_animation->setDirection( c->isActive() ? QAbstractAnimation::Forward : QAbstractAnimation::Backward );
             if( m_animation->state() != QAbstractAnimation::Running ) m_animation->start();
 
@@ -326,7 +326,7 @@
     //________________________________________________________________
     void Decoration::updateSizeGripVisibility()
     {
-        auto c = client().data();
+        auto c = client().toStrongRef().data();
         if( m_sizeGrip )
         { m_sizeGrip->setVisible( c->isResizeable() && !isMaximized() && !c->isShaded() ); }
     }
@@ -393,7 +393,7 @@
     //________________________________________________________________
     void Decoration::recalculateBorders()
     {
-        auto c = client().data();
+        auto c = client().toStrongRef().data();
         auto s = settings();
 
         // left, right and bottom borders
@@ -521,7 +521,7 @@
     void Decoration::paint(QPainter *painter, const QRect &repaintRegion)
     {
         // TODO: optimize based on repaintRegion
-        auto c = client().data();
+        auto c = client().toStrongRef().data();
         auto s = settings();
 
         // paint background
@@ -562,7 +562,7 @@
     //________________________________________________________________
     void Decoration::paintTitleBar(QPainter *painter, const QRect &repaintRegion)
     {
-        const auto c = client().data();
+        const auto c = client().toStrongRef().data();
         const QRect titleRect(QPoint(0, 0), QSize(size().width(), borderTop()));
 
         if ( !titleRect.intersects(repaintRegion) ) return;
@@ -660,7 +660,7 @@
         if( hideTitleBar() ) return qMakePair( QRect(), Qt::AlignCenter );
         else {
 
-            auto c = client().data();
+            auto c = client().toStrongRef().data();
             const int leftOffset = m_leftButtons->buttons().isEmpty() ?
                 Metrics::TitleBar_SideMargin*settings()->smallSpacing():
                 m_leftButtons->geometry().x() + m_leftButtons->geometry().width() + Metrics::TitleBar_SideMargin*settings()->smallSpacing();
@@ -804,7 +804,7 @@
         if( !QX11Info::isPlatformX11() ) return;
 
         // access client
-        auto c = client().data();
+        auto c = client().toStrongRef().data();
         if( !c ) return;
 
         if( c->windowId() != 0 )
diff --git a/kdecoration/breezesettingsprovider.cpp b/kdecoration/breezesettingsprovider.cpp
--- a/kdecoration/breezesettingsprovider.cpp
+++ b/kdecoration/breezesettingsprovider.cpp
@@ -75,7 +75,7 @@
         QString className;
 
         // get the client
-        auto client = decoration->client().data();
+        auto client = decoration->client().toStrongRef().data();
 
         foreach( auto internalSettings, m_exceptions )
         {
diff --git a/kdecoration/breezesizegrip.cpp b/kdecoration/breezesizegrip.cpp
--- a/kdecoration/breezesizegrip.cpp
+++ b/kdecoration/breezesizegrip.cpp
@@ -62,7 +62,7 @@
         updatePosition();
 
         // connections
-        auto c = decoration->client().data();
+        auto c = decoration->client().toStrongRef().data();
         connect( c, &KDecoration2::DecoratedClient::widthChanged, this, &SizeGrip::updatePosition );
         connect( c, &KDecoration2::DecoratedClient::heightChanged, this, &SizeGrip::updatePosition );
         connect( c, &KDecoration2::DecoratedClient::activeChanged, this, &SizeGrip::updateActiveState );
@@ -99,7 +99,7 @@
         #if BREEZE_HAVE_X11
 
         if( !QX11Info::isPlatformX11() ) return;
-        auto c = m_decoration.data()->client().data();
+        auto c = m_decoration.data()->client().toStrongRef().data();
 
         xcb_window_t windowId = c->windowId();
         if( windowId )
@@ -191,7 +191,7 @@
         #if BREEZE_HAVE_X11
         if( !QX11Info::isPlatformX11() ) return;
 
-        auto c = m_decoration.data()->client().data();
+        auto c = m_decoration.data()->client().toStrongRef().data();
         QPoint position(
             c->width() - GripSize - Offset,
             c->height() - GripSize - Offset );
@@ -213,7 +213,7 @@
         auto connection( QX11Info::connection() );
 
         // client
-        auto c = m_decoration.data()->client().data();
+        auto c = m_decoration.data()->client().toStrongRef().data();
 
         /*
         get root position matching position