Fix empty page added when showing OOB dialog (#4849)

src/widgets/Notebook.cpp

@@ -1439,6 +1439,11 @@ SplitContainer *SplitNotebook::getOrAddSelectedPage()
     return this->addPage();
 }
 
+SplitContainer *SplitNotebook::getSelectedPage()
+{
+    return dynamic_cast<SplitContainer *>(Notebook::getSelectedPage());
+}
+
 void SplitNotebook::select(QWidget *page, bool focusPage)
 {
     // If there's a previously selected page, go through its splits and

src/widgets/Notebook.hpp

@@ -209,6 +209,8 @@ public:
 
     SplitContainer *addPage(bool select = false);
     SplitContainer *getOrAddSelectedPage();
+    /// Returns `nullptr` when no page is selected.
+    SplitContainer *getSelectedPage();
     void select(QWidget *page, bool focusPage = true) override;
     void themeChangedEvent() override;
 

src/widgets/Window.cpp

@@ -109,7 +109,7 @@ bool Window::event(QEvent *event)
         }
 
         case QEvent::WindowDeactivate: {
-            auto page = this->notebook_->getOrAddSelectedPage();
+            auto *page = this->notebook_->getSelectedPage();
 
             if (page != nullptr)
             {
@@ -119,12 +119,8 @@ bool Window::event(QEvent *event)
                 {
                     split->updateLastReadMessage();
                 }
-            }
 
-            if (SplitContainer *container =
-                    dynamic_cast<SplitContainer *>(page))
-            {
-                container->hideResizeHandles();
+                page->hideResizeHandles();
             }
         }
         break;