kcm compositing: Hide preview option in Wayland

src/kcmkwin/kwincompositing/CMakeLists.txt

@@ -27,6 +27,7 @@ target_link_libraries(kwincompositing
     KF5::CoreAddons
     KF5::I18n
     KF5::KCMUtils
+    KF5::WindowSystem
 )
 
 install(TARGETS kwincompositing DESTINATION ${KDE_INSTALL_PLUGINDIR})

src/kcmkwin/kwincompositing/compositing.ui

@@ -216,7 +216,7 @@ you can reset this protection but be aware that this might result in an immediat
     </widget>
    </item>
    <item row="13" column="0">
-    <widget class="QLabel" name="label_6">
+    <widget class="QLabel" name="label_HiddenPreviews">
      <property name="text">
       <string>Keep window thumbnails:</string>
      </property>

src/kcmkwin/kwincompositing/main.cpp

@@ -18,6 +18,7 @@
 
 #include <kcmodule.h>
 #include <kservice.h>
+#include <KWindowSystem/KWindowSystem>
 
 #include <algorithm>
 #include <functional>
@@ -90,6 +91,10 @@ KWinCompositingKCM::KWinCompositingKCM(QWidget *parent, const QVariantList &args
 
     connect(this, &KWinCompositingKCM::defaultsIndicatorsVisibleChanged, this, &KWinCompositingKCM::updateUnmanagedItemStatus);
 
+    if (KWindowSystem::isPlatformWayland()) {
+        m_form.kcfg_HiddenPreviews->setVisible(false);
+        m_form.label_HiddenPreviews->setVisible(false);
+    }
     init();
 }