Added proper support for closable feature, now the close button is disabled for floating widgets

src/FloatingDockContainer.cpp

@@ -91,6 +91,17 @@ struct FloatingDockContainerPrivate
 	{
 		DraggingState = StateId;
 	}
+
+	/**
+	 * Disables the window close button if the content is not closable
+	 */
+	void disableCloseButton()
+	{
+		auto Flags = _this->windowFlags();
+		Flags |= Qt::CustomizeWindowHint;
+		Flags &= ~Qt::WindowCloseButtonHint;
+		_this->setWindowFlags(Flags);
+	}
 };
 // struct FloatingDockContainerPrivate
 
@@ -250,6 +261,10 @@ CFloatingDockContainer::CFloatingDockContainer(CDockAreaWidget* DockArea) :
 	CFloatingDockContainer(DockArea->dockManager())
 {
 	d->DockContainer->addDockArea(DockArea);
+	if (!DockArea->features().testFlag(CDockWidget::DockWidgetClosable))
+	{
+		d->disableCloseButton();
+	}
 }
 
 
@@ -258,6 +273,10 @@ CFloatingDockContainer::CFloatingDockContainer(CDockWidget* DockWidget) :
 	CFloatingDockContainer(DockWidget->dockManager())
 {
 	d->DockContainer->addDockWidget(CenterDockWidgetArea, DockWidget);
+	if (!DockWidget->features().testFlag(CDockWidget::DockWidgetClosable))
+	{
+		d->disableCloseButton();
+	}
 }
 
 //============================================================================
@@ -515,6 +534,10 @@ bool CFloatingDockContainer::restoreState(QXmlStreamReader& Stream, bool Testing
 	{
 		return false;
 	}
+	if (!d->DockContainer->features().testFlag(CDockWidget::DockWidgetClosable))
+	{
+		d->disableCloseButton();
+	}
 	onDockAreasAddedOrRemoved();
 	return true;
 }