diff --git a/abstract_wayland_output.cpp b/abstract_wayland_output.cpp
--- a/abstract_wayland_output.cpp
+++ b/abstract_wayland_output.cpp
@@ -18,6 +18,8 @@
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "abstract_wayland_output.h"
+
+#include "screens.h"
 #include "wayland_server.h"
 
 // KWayland
@@ -167,6 +169,7 @@
 {
     qCDebug(KWIN_CORE) << "Apply changes to the Wayland output.";
     bool emitModeChanged = false;
+    bool overallSizeCheckNeeded = false;
 
     // Enablement changes are handled by platform.
     if (changeSet->modeChanged()) {
@@ -185,13 +188,19 @@
         qCDebug(KWIN_CORE) << "Server setting position: " << changeSet->position();
         setGlobalPos(changeSet->position());
         // may just work already!
+        overallSizeCheckNeeded = true;
     }
     if (changeSet->scaleChanged()) {
         qCDebug(KWIN_CORE) << "Setting scale:" << changeSet->scale();
         setScale(changeSet->scaleF());
         emitModeChanged = true;
     }
 
+    overallSizeCheckNeeded |= emitModeChanged;
+    if (overallSizeCheckNeeded) {
+        emit screens()->changed();
+    }
+
     if (emitModeChanged) {
         emit modeChanged();
     }