avoid that another action triggers while aborting operation

sources/diagram.cpp

@@ -801,6 +801,11 @@ void Diagram::clearEventInterface()
 	}
 }
 
+bool Diagram::eventInterfaceIsRunning() const
+{
+	return m_event_interface && m_event_interface->isRunning();
+}
+
 /**
 	@brief Diagram::conductorsAutonumName
 	@return the name of autonum to use.

sources/diagram.h

@@ -216,7 +216,7 @@ class Diagram : public QGraphicsScene
 		// methods related to graphics items addition/removal on the diagram
 		virtual void addItem    (QGraphicsItem *item);
 		virtual void removeItem (QGraphicsItem *item);
-		bool hasEventInterface() const { return m_event_interface != nullptr; }
+		bool eventInterfaceIsRunning() const;
 	
 		// methods related to graphics options
 		ExportProperties applyProperties(const ExportProperties &);

sources/diagramevent/diagrameventaddpaste.cpp

@@ -87,12 +87,14 @@ DiagramEventAddPaste::DiagramEventAddPaste(Diagram *diagram, const QPointF &star
 */
 DiagramEventAddPaste::~DiagramEventAddPaste()
 {
-	if (!m_finished) {
+	if (!m_finished && m_diagram) {
 		removeItems();
 		m_finished = true;
 		m_running = false;
 	}
-	if (m_status_bar) m_status_bar->clearMessage();
+	if (m_status_bar) {
+		m_status_bar->clearMessage();
+	}
 }
 
 /**
@@ -164,13 +166,13 @@ void DiagramEventAddPaste::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
 {
 	if (!m_running) return;
 
+	event->setAccepted(true);
 	if (event->button() == Qt::LeftButton) {
 		moveTo(event->scenePos());
 		commit();
 	} else if (event->button() == Qt::RightButton) {
 		cancel();
 	}
-	event->setAccepted(true);
 }
 
 void DiagramEventAddPaste::keyPressEvent(QKeyEvent *event)
@@ -179,15 +181,15 @@ void DiagramEventAddPaste::keyPressEvent(QKeyEvent *event)
 
 	switch (event->key()) {
 		case Qt::Key_Escape:
-			cancel();
 			event->setAccepted(true);
+			cancel();
 			break;
 			//Return and Enter drop the paste where it stands, so the whole
 			//operation can be completed without a mouse.
 		case Qt::Key_Return:
 		case Qt::Key_Enter:
-			commit();
 			event->setAccepted(true);
+			commit();
 			break;
 		default:
 			break;

sources/diagramview.cpp

@@ -733,7 +733,7 @@ void DiagramView::keyPressEvent(QKeyEvent *e)
 				//way off the canvas for someone working without a mouse.
 				//Escape steps back out: first it drops the selection, then it
 				//hands focus to the next widget.
-			if (m_diagram && m_diagram->hasEventInterface()) {
+			if (m_diagram && m_diagram->eventInterfaceIsRunning()) {
 				QGraphicsView::keyPressEvent(e);  // let the active tool see it
 				return;
 			}