fix #784,ignore top/bottom auto-hide panels

--a bottom or top auto-hide panel is not considered
in the calculations for the availableScreenRegion

app/dockcorona.cpp

@@ -357,7 +357,8 @@ QRegion DockCorona::availableScreenRegion(int id) const
     QRegion available(screen->geometry());
 
     for (const auto *view : m_dockViews) {
-        if (view && view->containment() && view->screen() == screen) {
+        if (view && view->containment() && view->screen() == screen
+            && view->visibility() && (view->visibility()->mode() != Latte::Dock::AutoHide)) {
             int realThickness = view->normalThickness() - view->shadow();
 
             // Usually availableScreenRect is used by the desktop,

app/visibilitymanager.cpp

@@ -562,6 +562,11 @@ void VisibilityManagerPrivate::viewEventManager(QEvent *ev)
 VisibilityManager::VisibilityManager(PlasmaQuick::ContainmentView *view)
     : d(new VisibilityManagerPrivate(view, this))
 {
+    DockView *dockView = qobject_cast<DockView *>(view);
+
+    if (dockView) {
+        connect(this, &VisibilityManager::modeChanged, dockView->corona(), &Plasma::Corona::availableScreenRectChanged);
+    }
 }
 
 VisibilityManager::~VisibilityManager()