Speed up opening big projects with lazy folios

sources/ui/diagrambgcolorbutton.cpp

@@ -150,8 +150,9 @@ void DiagramBgColorToolButton::applyColor(const QColor &color)
 	if (!editor) {
 		return;
 	}
+		//A folio not built yet takes the colour when it is drawn
 	for (ProjectView *pv : editor->openedProjects())
-		for (Diagram *d : pv->project()->diagrams())
+		for (Diagram *d : pv->project()->folios())
 			d->update();
 }
 
@@ -175,8 +176,9 @@ void DiagramBgColorToolButton::applySystemColor()
 	if (!editor) {
 		return;
 	}
+		//A folio not built yet takes the colour when it is drawn
 	for (ProjectView *pv : editor->openedProjects())
-		for (Diagram *d : pv->project()->diagrams())
+		for (Diagram *d : pv->project()->folios())
 			d->update();
 }
 

sources/ui/diagrameditorhandlersizewidget.cpp

@@ -60,7 +60,8 @@ void DiagramEditorHandlerSizeWidget::on_comboBox_currentIndexChanged(int index)
 	{
 		editor_->setProperty("graphics_handler_size", size);
 		for (auto project_view : editor_->openedProjects()) {
-			for (auto diagram : project_view->project()->diagrams()) {
+				//Handles exist on built folios only
+			for (auto diagram : project_view->project()->builtFolios()) {
 				for (const auto item : diagram->items()) {
 					if (item->type() == QetGraphicsHandlerItem::Type) {
 						auto handler = qgraphicsitem_cast<QetGraphicsHandlerItem *>(item);

sources/ui/jumptoelementdialog.cpp

@@ -169,7 +169,7 @@ void JumpToElementDialog::activateCurrentItem()
 	const int index = current->data(Qt::UserRole).toInt();
 	if (index == -1) {
 		const QList<Diagram *> diagrams = m_diagram->project()
-				? m_diagram->project()->diagrams()
+				? m_diagram->project()->folios()
 				: QList<Diagram *>();
 		const int folio = current->data(Qt::UserRole + 2).toInt();
 		if (folio >= 0 && folio < diagrams.size()) {
@@ -208,7 +208,8 @@ QListWidgetItem *JumpToElementDialog::cellItem(const QString &needle) const
 	if (!m_diagram || !m_diagram->project()) {
 		return nullptr;
 	}
-	const QList<Diagram *> diagrams = m_diagram->project()->diagrams();
+		//Folios' cells only (their border): folios() builds nothing
+	const QList<Diagram *> diagrams = m_diagram->project()->folios();
 
 	Diagram *diagram = m_diagram;
 	QString cell = needle;