diff --git a/atoms.cpp b/atoms.cpp
index 439e37ecfe..98cd091d33 100644
--- a/atoms.cpp
+++ b/atoms.cpp
@@ -50,7 +50,6 @@ Atoms::Atoms()
     , net_wm_sync_request_counter(QByteArrayLiteral("_NET_WM_SYNC_REQUEST_COUNTER"))
     , net_wm_sync_request(QByteArrayLiteral("_NET_WM_SYNC_REQUEST"))
     , kde_net_wm_shadow(QByteArrayLiteral("_KDE_NET_WM_SHADOW"))
-    , net_wm_opaque_region(QByteArrayLiteral("_NET_WM_OPAQUE_REGION"))
     , kde_net_wm_tab_group(QByteArrayLiteral("_KDE_NET_WM_TAB_GROUP"))
     , kde_first_in_window_list(QByteArrayLiteral("_KDE_FIRST_IN_WINDOWLIST"))
     , kde_color_sheme(QByteArrayLiteral("_KDE_NET_WM_COLOR_SCHEME"))
diff --git a/atoms.h b/atoms.h
index 6badfc528e..0873d5e442 100644
--- a/atoms.h
+++ b/atoms.h
@@ -59,7 +59,6 @@ public:
     Xcb::Atom net_wm_sync_request_counter;
     Xcb::Atom net_wm_sync_request;
     Xcb::Atom kde_net_wm_shadow;
-    Xcb::Atom net_wm_opaque_region;
     Xcb::Atom kde_net_wm_tab_group;
     Xcb::Atom kde_first_in_window_list;
     Xcb::Atom kde_color_sheme;
diff --git a/events.cpp b/events.cpp
index 05aaddca6f..636d43c1b9 100644
--- a/events.cpp
+++ b/events.cpp
@@ -638,6 +638,9 @@ bool Client::windowEvent(xcb_generic_event_t *e)
         if (dirtyProperties2.testFlag(NET::WM2Urgency)) {
             updateUrgency();
         }
+        if (dirtyProperties2 & NET::WM2OpaqueRegion) {
+            getWmOpaqueRegion();
+        }
     }
 
     const uint8_t eventType = e->response_type & ~0x80;
@@ -1587,6 +1590,9 @@ bool Unmanaged::windowEvent(xcb_generic_event_t *e)
             emit opacityChanged(this, old_opacity);
         }
     }
+    if (dirtyProperties2 & NET::WM2OpaqueRegion) {
+        getWmOpaqueRegion();
+    }
     if (dirtyProperties2.testFlag(NET::WM2WindowRole)) {
         emit windowRoleChanged();
     }
@@ -1671,8 +1677,6 @@ void Toplevel::propertyNotifyEvent(xcb_property_notify_event_t *e)
             getWmClientLeader();
         else if (e->atom == atoms->kde_net_wm_shadow)
             getShadow();
-        else if (e->atom == atoms->net_wm_opaque_region)
-            getWmOpaqueRegion();
         else if (e->atom == atoms->kde_skip_close_animation)
             getSkipCloseAnimation();
         break;
diff --git a/manage.cpp b/manage.cpp
index 96c015e7ed..21a11dcdc9 100644
--- a/manage.cpp
+++ b/manage.cpp
@@ -96,7 +96,8 @@ bool Client::manage(xcb_window_t w, bool isMapped)
         NET::WM2Input |
         NET::WM2Protocols |
         NET::WM2InitialMappingState |
-        NET::WM2IconPixmap;
+        NET::WM2IconPixmap |
+        NET::WM2OpaqueRegion;
 
     auto wmClientLeaderCookie = fetchWmClientLeader();
     auto skipCloseAnimationCookie = fetchSkipCloseAnimation();
diff --git a/netinfo.cpp b/netinfo.cpp
index e004e1d189..87aeaab83e 100644
--- a/netinfo.cpp
+++ b/netinfo.cpp
@@ -106,7 +106,8 @@ RootInfo *RootInfo::create()
         NET::WM2DesktopLayout |
         NET::WM2FullPlacement |
         NET::WM2FullscreenMonitors |
-        NET::WM2KDEShadow;
+        NET::WM2KDEShadow |
+        NET::WM2OpaqueRegion;
 #ifdef KWIN_BUILD_ACTIVITIES
         properties2 |= NET::WM2Activities;
 #endif
diff --git a/toplevel.cpp b/toplevel.cpp
index 3ab44129d7..c8fcf39edb 100644
--- a/toplevel.cpp
+++ b/toplevel.cpp
@@ -364,38 +364,11 @@ bool Toplevel::wantsShadowToBeRendered() const
 
 void Toplevel::getWmOpaqueRegion()
 {
-    const int length=32768;
-    unsigned long bytes_after_return=0;
+    const auto rects = info->opaqueRegion();
     QRegion new_opaque_region;
-    do {
-        unsigned long* data;
-        Atom type;
-        int rformat;
-        unsigned long nitems;
-        if (XGetWindowProperty(display(), m_client,
-                               atoms->net_wm_opaque_region, 0, length, false, XCB_ATOM_CARDINAL,
-                               &type, &rformat, &nitems, &bytes_after_return,
-                               reinterpret_cast< unsigned char** >(&data)) == Success) {
-            if (type != XCB_ATOM_CARDINAL || rformat != 32 || nitems%4) {
-                // it can happen, that the window does not provide this property
-                XFree(data);
-                break;
-            }
-
-            for (unsigned int i = 0; i < nitems;) {
-                const int x = data[i++];
-                const int y = data[i++];
-                const int w = data[i++];
-                const int h = data[i++];
-
-                new_opaque_region += QRect(x,y,w,h);
-            }
-            XFree(data);
-        } else {
-            qCWarning(KWIN_CORE) << "XGetWindowProperty failed";
-            break;
-        }
-    } while (bytes_after_return > 0);
+    for (const auto &r : rects) {
+        new_opaque_region += QRect(r.pos.x, r.pos.y, r.size.width, r.size.height);
+    }
 
     opaque_region = new_opaque_region;
 }
diff --git a/unmanaged.cpp b/unmanaged.cpp
index 642713af3b..689cd76004 100644
--- a/unmanaged.cpp
+++ b/unmanaged.cpp
@@ -71,7 +71,8 @@ bool Unmanaged::track(Window w)
                           NET::WMWindowType | NET::WMPid,
                           NET::WM2Opacity |
                           NET::WM2WindowRole |
-                          NET::WM2WindowClass);
+                          NET::WM2WindowClass |
+                          NET::WM2OpaqueRegion);
     getResourceClass();
     getWmClientLeader();
     getWmClientMachine();