Fix bug #8069: View/Update other formats button disabled with non-TeX fonts

src/frontends/qt4/GuiToolbar.cpp

@@ -204,6 +204,7 @@ void MenuButton::mousePressEvent(QMouseEvent * e)
 	m->setWindowTitle(label);
 	m->setTearOffEnabled(true);
 	connect(bar_, SIGNAL(updated()), m, SLOT(updateParent()));
+	connect(bar_, SIGNAL(updated()), this, SLOT(updateTriggered()));
 	ToolbarInfo const * tbinfo = guiApp->toolbars().info(tbitem_.name_);
 	if (!tbinfo) {
 		LYXERR0("Unknown toolbar " << tbitem_.name_);
@@ -227,6 +228,28 @@ void MenuButton::actionTriggered(QAction * action)
 }
 
 
+void MenuButton::updateTriggered()
+{
+	if (!menu())
+		return;
+
+	bool enabled = false;
+	QList<QAction *> acts = menu()->actions();
+	for (int i = 0; i < acts.size(); ++i)
+		if (acts[i]->isEnabled()) {
+			enabled = true;
+			break;
+		}
+	// Enable the MenuButton if at least one menu item is enabled
+	setEnabled(enabled);
+	// If a disabled item is default, switch to InstantPopup
+	// (this can happen if a user selects e.g. DVI and then
+	// turns non-TeX fonts on)
+	if (defaultAction() && !defaultAction()->isEnabled())
+		setPopupMode(QToolButton::InstantPopup);
+}
+
+
 void GuiToolbar::add(ToolbarItem const & item)
 {
 	switch (item.type_) {

src/frontends/qt4/GuiToolbar.h

@@ -59,6 +59,8 @@ private:
 private Q_SLOTS:
 	///
 	void actionTriggered(QAction * action);
+	///
+	void updateTriggered();
 };
 
 

status.20x

@@ -76,6 +76,9 @@ What's new
 
 * USER INTERFACE
 
+- Do not disable View/Update Other Formats button when "Use non-TeX fonts"
+  is active (bug 8069).
+
 - Do not allow to add a citation in the citation dialog using the
   <Enter> key if the Add button is disabled.