Properly implemented setting enable state of dock area close button

src/DockAreaWidget.cpp

@@ -54,6 +54,8 @@
 #include "DockSplitter.h"
 #include "DockAreaTitleBar.h"
 
+#include <iostream>
+
 
 namespace ads
 {
@@ -242,6 +244,7 @@ struct DockAreaWidgetPrivate
 	DockAreaLayout* ContentsLayout;
 	CDockAreaTitleBar* TitleBar;
 	CDockManager* DockManager = nullptr;
+	bool UpdateCloseButton = false;
 
 	/**
 	 * Private data constructor
@@ -293,6 +296,11 @@ struct DockAreaWidgetPrivate
 	{
 		return TitleBar->tabBar();
 	}
+
+	/**
+	 * Udpates the enable state of the close button
+	 */
+	void updateCloseButtonState();
 };
 // struct DockAreaWidgetPrivate
 
@@ -319,6 +327,25 @@ void DockAreaWidgetPrivate::createTitleBar()
 }
 
 
+//============================================================================
+void DockAreaWidgetPrivate::updateCloseButtonState()
+{
+	if (_this->isHidden())
+	{
+		UpdateCloseButton = true;
+		return;
+	}
+
+	if (!UpdateCloseButton)
+	{
+		return;
+	}
+	TitleBar->button(TitleBarButtonClose)->setEnabled(
+		_this->features().testFlag(CDockWidget::DockWidgetClosable));
+	UpdateCloseButton = false;
+}
+
+
 //============================================================================
 CDockAreaWidget::CDockAreaWidget(CDockManager* DockManager, CDockContainerWidget* parent) :
 	QFrame(parent),
@@ -383,6 +410,7 @@ void CDockAreaWidget::insertDockWidget(int index, CDockWidget* DockWidget,
 		setCurrentIndex(index);
 	}
 	DockWidget->setDockArea(this);
+	d->updateCloseButtonState();
 }
 
 
@@ -414,6 +442,7 @@ void CDockAreaWidget::removeDockWidget(CDockWidget* DockWidget)
 		hideAreaWithNoVisibleContent();
 	}
 
+	d->updateCloseButtonState();
 	updateTitleBarVisibility();
 	auto TopLevelDockWidget = dockContainer()->topLevelDockWidget();
 	if (TopLevelDockWidget)
@@ -730,10 +759,19 @@ CDockWidget::DockWidgetFeatures CDockAreaWidget::features() const
 void CDockAreaWidget::toggleView(bool Open)
 {
 	setVisible(Open);
+
 	emit viewToggled(Open);
 }
 
 
+//============================================================================
+void CDockAreaWidget::setVisible(bool Visible)
+{
+	Super::setVisible(Visible);
+	d->updateCloseButtonState();
+}
+
+
 //============================================================================
 QAbstractButton* CDockAreaWidget::titleBarButton(TitleBarButton which) const
 {

src/DockAreaWidget.h

@@ -241,6 +241,11 @@ public:
 	 */
 	QAbstractButton* titleBarButton(TitleBarButton which) const;
 
+	/**
+	 * Update the close button if visibility changed
+	 */
+	virtual void setVisible(bool Visible) override;
+
 public slots:
 	/**
 	 * This activates the tab for the given tab index.

src/DockContainerWidget.cpp

@@ -627,11 +627,10 @@ bool DockContainerWidgetPrivate::restoreDockArea(QXmlStreamReader& s,
 		}
 
 		qDebug() << "Dock Widget found - parent " << DockWidget->parent();
-		DockArea->addDockWidget(DockWidget);
-
 		// We hide the DockArea here to prevent the short display (the flashing)
 		// of the dock areas during application startup
 		DockArea->hide();
+		DockArea->addDockWidget(DockWidget);
 		DockWidget->setToggleViewActionChecked(!Closed);
 		DockWidget->setClosedState(Closed);
 		DockWidget->setProperty("closed", Closed);

src/DockWidget.h

@@ -152,6 +152,23 @@ public:
 		StateFloating
 	};
 
+	/**
+	 * Sets the widget for the dock widget to widget.
+	 * The InsertMode defines how the widget is inserted into the dock widget.
+	 * The content of a dock widget should be resizable do a very small size to
+	 * prevent the dock widget from blocking the resizing. To ensure, that a
+	 * dock widget can be resized very well, it is better to insert the content+
+	 * widget into a scroll area or to provide a widget that is already a scroll
+	 * area or that contains a scroll area.
+	 * If the InsertMode is AutoScrollArea, the DockWidget tries to automatically
+	 * detect how to insert the given widget. If the widget is derived from
+	 * QScrollArea (i.e. an QAbstractItemView), then the widget is inserted
+	 * directly. If the given widget is not a scroll area, the widget will be
+	 * inserted into a scroll area.
+	 * To force insertion into a scroll area, you can also provide the InsertMode
+	 * ForceScrollArea. To prevent insertion into a scroll area, you can
+	 * provide the InsertMode ForceNoScrollArea
+	 */
 	enum eInsertMode
 	{
 		AutoScrollArea,