diff --git a/autotests/integration/shell_client_test.cpp b/autotests/integration/shell_client_test.cpp
--- a/autotests/integration/shell_client_test.cpp
+++ b/autotests/integration/shell_client_test.cpp
@@ -778,6 +778,8 @@
     auto c = Test::renderAndWaitForShown(surface.data(), QSize(100, 50), Qt::blue);
     QVERIFY(c);
     QCOMPARE(c->desktopFileName(), QByteArrayLiteral("org.kde.foo"));
+    QCOMPARE(c->resourceClass(), QByteArrayLiteral("org.kde.foo"));
+    QVERIFY(c->resourceName().startsWith("testShellClient"));
     // the desktop file does not exist, so icon should be generic Wayland
     QCOMPARE(c->icon().name(), QStringLiteral("wayland"));
 
@@ -788,6 +790,8 @@
     shellSurface->setAppId(QByteArrayLiteral("org.kde.bar"));
     QVERIFY(desktopFileNameChangedSpy.wait());
     QCOMPARE(c->desktopFileName(), QByteArrayLiteral("org.kde.bar"));
+    QCOMPARE(c->resourceClass(), QByteArrayLiteral("org.kde.bar"));
+    QVERIFY(c->resourceName().startsWith("testShellClient"));
     // icon should still be wayland
     QCOMPARE(c->icon().name(), QStringLiteral("wayland"));
     QVERIFY(iconChangedSpy.isEmpty());
diff --git a/shell_client.cpp b/shell_client.cpp
--- a/shell_client.cpp
+++ b/shell_client.cpp
@@ -51,6 +51,7 @@
 
 #include <KDesktopFile>
 
+#include <QFileInfo>
 #include <QOpenGLFramebufferObject>
 #include <QWindow>
 
@@ -126,11 +127,18 @@
         }
     );
 
-    setResourceClass(shellSurface->windowClass());
+    // determine the resource name, this is inspired from ICCCM 4.1.2.5
+    // the binary name of the invoked client
+    QFileInfo info{shellSurface->client()->executablePath()};
+    QByteArray resourceName;
+    if (info.exists()) {
+        resourceName = info.fileName().toUtf8();
+    }
+    setResourceClass(resourceName, shellSurface->windowClass());
     setDesktopFileName(shellSurface->windowClass());
     connect(shellSurface, &T::windowClassChanged, this,
-        [this] (const QByteArray &windowClass) {
-            setResourceClass(windowClass);
+        [this, resourceName] (const QByteArray &windowClass) {
+            setResourceClass(resourceName, windowClass);
             setDesktopFileName(windowClass);
         }
     );