diff --git a/applets/taskmanager/package/contents/ui/Task.qml b/applets/taskmanager/package/contents/ui/Task.qml
index 6347c8d5564e6d7b20558d00a5cc0932a3aa8acd..f54c37bb26fb0f5df46280634fc74c13b64d08c9 100644
--- a/applets/taskmanager/package/contents/ui/Task.qml
+++ b/applets/taskmanager/package/contents/ui/Task.qml
@@ -5,6 +5,7 @@
 */
 
 import QtQuick 2.0
+import QtGraphicalEffects 1.12
 
 import org.kde.plasma.core 2.0 as PlasmaCore
 import org.kde.plasma.components 2.0 as PlasmaComponents
@@ -415,13 +416,53 @@ MouseArea {
         PlasmaCore.IconItem {
             id: icon
 
-            anchors.fill: parent
+            anchors {
+                centerIn: parent
+                verticalCenterOffset: m.IsGroupParent === true && !taskSvg.hasExpanderGraphics ? Math.round(PlasmaCore.Units.smallSpacing/2) : 0
+                horizontalCenterOffset: m.IsGroupParent === true && !taskSvg.hasExpanderGraphics ? -Math.round(PlasmaCore.Units.smallSpacing/2) : 0
+            }
+            width: parent.width
+            height: parent.height
 
             active: task.highlighted
             enabled: true
             usesPlasmaTheme: false
 
             source: model.decoration
+
+            // Shadow behind this icon when showing another copy behind it when
+            // using Plasma themes that don't have their own grouped task icon
+            layer.enabled:  m.IsGroupParent === true && !taskSvg.hasExpanderGraphics
+            layer.effect: DropShadow {
+                cached: true
+                color: "dimgray"
+                samples: 7 // 2 fewer than default to reduce resource use
+                horizontalOffset: 1
+                verticalOffset: -1
+            }
+        }
+
+        // Secondary icon behind the first one for grouped tasks when using
+        // Plasma themes that don't have their own grouped task icon
+        Loader {
+            anchors {
+                centerIn: parent
+                verticalCenterOffset: -Math.round(PlasmaCore.Units.smallSpacing/2)
+                horizontalCenterOffset: Math.round(PlasmaCore.Units.smallSpacing/2)
+            }
+            width: parent.width
+            height: parent.height
+            z: -1
+
+            active: m.IsGroupParent === true && !taskSvg.hasExpanderGraphics
+            sourceComponent: PlasmaCore.IconItem {
+                active: task.highlighted
+                enabled: true
+                opacity: 0.7
+                usesPlasmaTheme: false
+
+                source: model.decoration
+            }
         }
 
         Loader {
@@ -562,7 +603,7 @@ MouseArea {
     ]
 
     Component.onCompleted: {
-        if (!inPopup && model.IsWindow === true) {
+        if (!inPopup && model.IsWindow === true && taskSvg.hasExpanderGraphics) {
             var component = Qt.createComponent("GroupExpanderOverlay.qml");
             component.createObject(task);
         }
diff --git a/applets/taskmanager/package/contents/ui/main.qml b/applets/taskmanager/package/contents/ui/main.qml
index 7ae148ec8dbb26b5bbbdda3038580da308367eb0..cbb1f4bf1bd4f4bd13eb8b7b39f0a658a978d2b7 100644
--- a/applets/taskmanager/package/contents/ui/main.qml
+++ b/applets/taskmanager/package/contents/ui/main.qml
@@ -378,6 +378,11 @@ MouseArea {
     PlasmaCore.Svg {
         id: taskSvg
 
+        readonly property bool hasExpanderGraphics: hasElement("group-expander-left")
+                                                 && hasElement("group-expander-right")
+                                                 && hasElement("group-expander-top")
+                                                 && hasElement("group-expander-bottom")
+
         imagePath: "widgets/tasks"
     }