diff --git a/autotests/client/test_plasmashell.cpp b/autotests/client/test_plasmashell.cpp
--- a/autotests/client/test_plasmashell.cpp
+++ b/autotests/client/test_plasmashell.cpp
@@ -54,6 +54,7 @@
     void testPanelTakesFocus();
     void testDisconnect();
     void testWhileDestroying();
+    void testPopupBehavior();
 
 private:
     Display *m_display = nullptr;
@@ -526,5 +527,39 @@
     QVERIFY(clientErrorSpy.isEmpty());
 }
 
+void TestPlasmaShell::testPopupBehavior()
+{
+    // this test verifies that the popup behavior is properly passed to the server
+    QSignalSpy plasmaSurfaceCreatedSpy(m_plasmaShellInterface, &PlasmaShellInterface::surfaceCreated);
+    QVERIFY(plasmaSurfaceCreatedSpy.isValid());
+
+    QScopedPointer<Surface> s(m_compositor->createSurface());
+    QScopedPointer<PlasmaShellSurface> ps(m_plasmaShell->createSurface(s.data()));
+    QVERIFY(plasmaSurfaceCreatedSpy.wait());
+    QCOMPARE(plasmaSurfaceCreatedSpy.count(), 1);
+
+    // verify that we got a plasma shell surface
+    auto sps = plasmaSurfaceCreatedSpy.first().first().value<PlasmaShellSurfaceInterface*>();
+    QVERIFY(sps);
+    QVERIFY(sps->surface());
+    QCOMPARE(sps->popupBehavior(), 0);
+
+    // now change the behavior
+    QSignalSpy behaviorChangedSpy(sps, &PlasmaShellSurfaceInterface::popupBehaviorChanged);
+    QVERIFY(behaviorChangedSpy.isValid());
+    ps->setPopupBehavior(PlasmaShellSurface::PopupBehavior::AlwaysOnTop);
+    QVERIFY(behaviorChangedSpy.wait());
+    QCOMPARE(sps->popupBehavior(), PlasmaShellSurfaceInterface::PopupBehavior::AlwaysOnTop);
+
+    // changing to same should not trigger the signal
+    ps->setPopupBehavior(PlasmaShellSurface::PopupBehavior::AlwaysOnTop);
+    QVERIFY(!behaviorChangedSpy.wait(100));
+
+    // but changing back to Always Visible should work
+    ps->setPopupBehavior(PlasmaShellSurface::PopupBehaviorFlags());
+    QVERIFY(behaviorChangedSpy.wait());
+    QCOMPARE(sps->popupBehavior(), PlasmaShellSurfaceInterface::PopupBehaviorFlags());
+}
+
 QTEST_GUILESS_MAIN(TestPlasmaShell)
 #include "test_plasmashell.moc"
diff --git a/src/client/plasmashell.h b/src/client/plasmashell.h
--- a/src/client/plasmashell.h
+++ b/src/client/plasmashell.h
@@ -333,6 +333,23 @@
      **/
     void setPanelTakesFocus(bool takesFocus);
 
+    /**
+     * Describes how a PlasmaShellSurface should behave.
+     * Applies to all roles except Panel
+     * Choosing to honor this is up to the compositor
+     * @since 5.FIXME
+     **/
+    enum class PopupBehavior {
+        AlwaysOnTop = 1,
+    };
+    Q_DECLARE_FLAGS(PopupBehaviorFlags, PopupBehavior)
+
+    /**
+     * Sets the PopupBehavior for a PlasmaShellSurface
+     * @since 5.FIXME
+     **/
+    void setPopupBehavior(PopupBehaviorFlags behavior);
+
 Q_SIGNALS:
     /**
      * Emitted when the compositor hided an auto hiding panel.
@@ -363,5 +380,5 @@
 
 Q_DECLARE_METATYPE(KWayland::Client::PlasmaShellSurface::Role)
 Q_DECLARE_METATYPE(KWayland::Client::PlasmaShellSurface::PanelBehavior)
-
+Q_DECLARE_OPERATORS_FOR_FLAGS(KWayland::Client::PlasmaShellSurface::PopupBehaviorFlags)
 #endif
diff --git a/src/client/plasmashell.cpp b/src/client/plasmashell.cpp
--- a/src/client/plasmashell.cpp
+++ b/src/client/plasmashell.cpp
@@ -342,5 +342,19 @@
     org_kde_plasma_surface_set_panel_takes_focus(d->surface, takesFocus);
 }
 
+void PlasmaShellSurface::setPopupBehavior(PlasmaShellSurface::PopupBehaviorFlags behavior)
+{
+    Q_ASSERT(isValid());
+    if (wl_proxy_get_version(d->surface) < ORG_KDE_PLASMA_SURFACE_SET_POPUP_BEHAVIOR_SINCE_VERSION) {
+        return;
+    }
+    uint32_t wlRole = 0;
+    if (behavior & PopupBehavior::AlwaysOnTop) {
+        wlRole |= ORG_KDE_PLASMA_SURFACE_POPUP_BEHAVIOR_ALWAYS_ON_TOP;
+    }
+    org_kde_plasma_surface_set_popup_behavior(d->surface, wlRole);
+}
+
+
 }
 }
diff --git a/src/client/protocols/plasma-shell.xml b/src/client/protocols/plasma-shell.xml
--- a/src/client/protocols/plasma-shell.xml
+++ b/src/client/protocols/plasma-shell.xml
@@ -17,7 +17,7 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
   ]]></copyright>
 
-  <interface name="org_kde_plasma_shell" version="5">
+  <interface name="org_kde_plasma_shell" version="6">
     <description summary="create shell windows and helpers">
       This interface is used by KF5 powered Wayland shells to communicate with
       the compositor and can only be bound one time.
@@ -130,7 +130,7 @@
     -->
   </interface>
 
-  <interface name="org_kde_plasma_surface" version="5">
+  <interface name="org_kde_plasma_surface" version="6">
     <description summary="metadata interface">
       An interface that may be implemented by a wl_surface, for
       implementations that provide the shell user interface.
@@ -319,7 +319,7 @@
     </enum>
 
     <request name="set_panel_behavior">
-      <description summary="set or unset the panel ">
+      <description summary="set or unset the panel">
         Set flags bitmask as described by the flag enum.
         Pass 0 to unset any flag, the surface will adjust its behavior to
         the default.
@@ -393,5 +393,21 @@
         <arg name="skip" type="uint" summary="Boolean value that sets whether to skip the window switcher."/>
      </request>
 
+    <enum name="popup_behavior" since="6">
+      <description summary="Behavior for popup surfaces">
+      </description>
+      <entry name="always_on_top" value="1" summary="popup stays above other windows">
+        The popup dialog remains above other windows
+      </entry>
+    </enum>
+
+    <request name="set_popup_behavior" since="6">
+      <description summary="set or unset the popup flags">
+        Set flags bitmask as described by the flag enum.
+        Pass 0 to unset any flag, the surface will adjust its behavior to
+        the default.
+      </description>
+      <arg name="flags" type="uint" summary="popup_behavior enum value"/>
+    </request>
   </interface>
 </protocol>
diff --git a/src/client/registry.cpp b/src/client/registry.cpp
--- a/src/client/registry.cpp
+++ b/src/client/registry.cpp
@@ -169,7 +169,7 @@
         &Registry::subCompositorRemoved
     }},
     {Registry::Interface::PlasmaShell, {
-        5,
+        6,
         QByteArrayLiteral("org_kde_plasma_shell"),
         &org_kde_plasma_shell_interface,
         &Registry::plasmaShellAnnounced,
diff --git a/src/server/plasmashell_interface.h b/src/server/plasmashell_interface.h
--- a/src/server/plasmashell_interface.h
+++ b/src/server/plasmashell_interface.h
@@ -176,6 +176,17 @@
      **/
     bool panelTakesFocus() const;
 
+    enum class PopupBehavior {
+        AlwaysOnTop = 1, ///< The popup should stay above other windows
+    };
+    Q_DECLARE_FLAGS(PopupBehaviorFlags, PopupBehavior)
+
+    /**
+     * @returns The PopupBehavior for a PlasmaShellSurfaceInterface
+     * @since 5.FIXME
+     **/
+    PopupBehaviorFlags popupBehavior() const;
+
     /**
      * @returns The PlasmaShellSurfaceInterface for the @p native resource.
      * @since 5.5
@@ -233,6 +244,12 @@
      **/
     void panelAutoHideShowRequested();
 
+    /**
+     * A change of the popup behavior has been requested.
+     * @since 5.FIXME
+     **/
+    void popupBehaviorChanged();
+
 private:
     friend class PlasmaShellInterface;
     explicit PlasmaShellSurfaceInterface(PlasmaShellInterface *shell, SurfaceInterface *parent, wl_resource *parentResource);
@@ -245,5 +262,5 @@
 
 Q_DECLARE_METATYPE(KWayland::Server::PlasmaShellSurfaceInterface::Role)
 Q_DECLARE_METATYPE(KWayland::Server::PlasmaShellSurfaceInterface::PanelBehavior)
-
+Q_DECLARE_OPERATORS_FOR_FLAGS(KWayland::Server::PlasmaShellSurfaceInterface::PopupBehaviorFlags)
 #endif
diff --git a/src/server/plasmashell_interface.cpp b/src/server/plasmashell_interface.cpp
--- a/src/server/plasmashell_interface.cpp
+++ b/src/server/plasmashell_interface.cpp
@@ -50,7 +50,7 @@
     static const quint32 s_version;
 };
 
-const quint32 PlasmaShellInterface::Private::s_version = 5;
+const quint32 PlasmaShellInterface::Private::s_version = 6;
 
 PlasmaShellInterface::Private::Private(PlasmaShellInterface *q, Display *d)
     : Global::Private(d, &org_kde_plasma_shell_interface, s_version)
@@ -73,8 +73,9 @@
     SurfaceInterface *surface;
     QPoint m_globalPos;
     Role m_role = Role::Normal;
-    bool m_positionSet = false;
     PanelBehavior m_panelBehavior = PanelBehavior::AlwaysVisible;
+    PopupBehaviorFlags m_popupBehavior;
+    bool m_positionSet = false;
     bool m_skipTaskbar = false;
     bool m_skipSwitcher = false;
     bool panelTakesFocus = false;
@@ -90,10 +91,12 @@
     static void panelAutoHideHideCallback(wl_client *client, wl_resource *resource);
     static void panelAutoHideShowCallback(wl_client *client, wl_resource *resource);
     static void panelTakesFocusCallback(wl_client *client, wl_resource *resource, uint32_t takesFocus);
+    static void setPopupBehaviorCallback(wl_client *client, wl_resource *resource, uint32_t flag);
 
     void setPosition(const QPoint &globalPos);
     void setRole(uint32_t role);
     void setPanelBehavior(org_kde_plasma_surface_panel_behavior behavior);
+    void setPopupBehavior(uint32_t behavior);
 
     PlasmaShellSurfaceInterface *q_func() {
         return reinterpret_cast<PlasmaShellSurfaceInterface *>(q);
@@ -168,7 +171,8 @@
     panelAutoHideHideCallback,
     panelAutoHideShowCallback,
     panelTakesFocusCallback,
-    setSkipSwitcherCallback
+    setSkipSwitcherCallback,
+    setPopupBehaviorCallback,
 };
 #endif
 
@@ -402,10 +406,39 @@
     return d->panelTakesFocus;
 }
 
+PlasmaShellSurfaceInterface::PopupBehaviorFlags PlasmaShellSurfaceInterface::popupBehavior() const
+{
+    Q_D();
+    return d->m_popupBehavior;
+}
+
 PlasmaShellSurfaceInterface *PlasmaShellSurfaceInterface::get(wl_resource *native)
 {
     return Private::get<PlasmaShellSurfaceInterface>(native);
 }
 
+void PlasmaShellSurfaceInterface::Private::setPopupBehaviorCallback(wl_client *client, wl_resource *resource, uint32_t flag)
+{
+    auto s = cast<Private>(resource);
+    Q_ASSERT(client == *s->client);
+    s->setPopupBehavior(flag);
+}
+
+
+void PlasmaShellSurfaceInterface::Private::setPopupBehavior(uint32_t behavior)
+{
+    PopupBehaviorFlags newBehavior;
+    if (behavior & ORG_KDE_PLASMA_SURFACE_POPUP_BEHAVIOR_ALWAYS_ON_TOP) {
+        newBehavior |= PopupBehavior::AlwaysOnTop;
+    }
+
+    if (m_popupBehavior == newBehavior) {
+        return;
+    }
+    m_popupBehavior = newBehavior;
+    Q_Q(PlasmaShellSurfaceInterface);
+    emit q->popupBehaviorChanged();
+}
+
 }
 }