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

src/DockAreaWidget.cpp

@@ -654,6 +654,19 @@ CDockWidget* CDockAreaWidget::nextOpenDockWidget(CDockWidget* DockWidget) const
 	}
 }
 
+
+//============================================================================
+CDockWidget::DockWidgetFeatures CDockAreaWidget::features() const
+{
+	CDockWidget::DockWidgetFeatures Features;
+	for (const auto DockWidget : dockWidgets())
+	{
+		Features &= DockWidget->features();
+	}
+
+	return Features;
+}
+
 } // namespace ads
 
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