recreate plasmashellsurf on exposed, destoy on hidden

Summary:
every time the window gets shown the wayland surfaces
get created, when hidden, they get destroyed

showevent is too early for it as they aren't there yet,
use :Exposed instead, but only the first time when the surface
isn't there yet

Test Plan:
popup applets always have correct blur in a wayland
session

Reviewers: #plasma, #plasma_on_wayland, davidedmundson

Reviewed By: #plasma, davidedmundson

Subscribers: davidedmundson, plasma-devel, #frameworks

Tags: #frameworks, #plasma_on_wayland

Differential Revision: https://phabricator.kde.org/D5745

src/declarativeimports/core/tooltipdialog.cpp

@@ -102,15 +102,6 @@ bool ToolTipDialog::event(QEvent *e)
         dismiss();
     }
 
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 5, 0))
-    if (e->type() == QEvent::PlatformSurface) {
-        auto pe = static_cast<QPlatformSurfaceEvent*>(e);
-        if (pe->surfaceEventType() == QPlatformSurfaceEvent::SurfaceCreated) {
-            KWindowSystem::setType(winId(), NET::Tooltip);
-        }
-    }
-#endif
-
     bool ret = Dialog::event(e);
     Qt::WindowFlags flags = Qt::ToolTip | Qt::WindowDoesNotAcceptFocus | Qt::WindowStaysOnTopHint;
     if (KWindowSystem::isPlatformX11()) {

src/plasmaquick/dialog.cpp

@@ -1120,27 +1120,43 @@ void Dialog::showEvent(QShowEvent *event)
 bool Dialog::event(QEvent *event)
 {
     if (event->type() == QEvent::Expose) {
-        // FIXME TODO: We can remove this once we depend on Qt 5.6.1+.
+        auto ee = static_cast<QExposeEvent*>(event);
-        // See: https://bugreports.qt.io/browse/QTBUG-26978
+
+        if (ee->region().isNull()) {
+            return QQuickWindow::event(event);
+        }
+
+        /*
+         * expose event is the only place where to correctly
+         * register our wayland extensions, as showevent is a bit too
+         * soon and the platform window isn't shown yet
+         * create a shell surface every time the window gets exposed
+         * (only the first expose event, guarded by shelldurface existence)
+         * and tear it down when the window gets hidden
+         * see https://phabricator.kde.org/T6064
+         */
+        if (!d->shellSurface) {
             KWindowSystem::setState(winId(), NET::SkipTaskbar | NET::SkipPager);
+            d->setupWaylandIntegration();
+            d->updateVisibility(true);
+        }
 #if (QT_VERSION > QT_VERSION_CHECK(5, 5, 0))
     } else if (event->type() == QEvent::PlatformSurface) {
         const QPlatformSurfaceEvent *pSEvent = static_cast<QPlatformSurfaceEvent *>(event);
 
         if (pSEvent->surfaceEventType() == QPlatformSurfaceEvent::SurfaceCreated) {
             KWindowSystem::setState(winId(), NET::SkipTaskbar | NET::SkipPager);
-            d->setupWaylandIntegration();
-        } else if (pSEvent->surfaceEventType() == QPlatformSurfaceEvent::SurfaceAboutToBeDestroyed) {
-#if HAVE_KWAYLAND
-            delete d->shellSurface;
-            d->shellSurface = nullptr;
-#endif
         }
 #endif
     } else if (event->type() == QEvent::Show) {
         d->updateVisibility(true);
     } else if (event->type() == QEvent::Hide) {
         d->updateVisibility(false);
+#if HAVE_KWAYLAND
+        delete d->shellSurface;
+        d->shellSurface = nullptr;
+#endif
+
     } else if (event->type() == QEvent::Move) {
         QMoveEvent *me = static_cast<QMoveEvent *>(event);
 #if HAVE_KWAYLAND