diff --git a/borderinset.cpp b/borderinset.cpp
index 0f64aa058..0bbd63b4e 100644
--- a/borderinset.cpp
+++ b/borderinset.cpp
@@ -94,7 +94,7 @@ void BorderInset::draw(QPainter *qp, qreal x, qreal y) {
 		qp -> drawText(inset_date,   Qt::AlignVCenter | Qt::AlignLeft,   tr(" Date : ") + bi_date.toString("dd/MM/yyyy"));
 		
 		qp -> drawRect(inset_title);
-		qp -> drawText(inset_title,  Qt::AlignVCenter | Qt::AlignCenter, tr("Titre du document: ") + bi_title);
+		qp -> drawText(inset_title,  Qt::AlignVCenter | Qt::AlignCenter, tr("Titre du document : ") + bi_title);
 		
 		qp -> drawRect(inset_file);
 		qp -> drawText(inset_file,   Qt::AlignVCenter | Qt::AlignLeft,   tr(" Fichier : ") + bi_filename);
diff --git a/conducer.cpp b/conducer.cpp
index 531aafde9..5531f9258 100644
--- a/conducer.cpp
+++ b/conducer.cpp
@@ -168,7 +168,13 @@ void Conducer::priv_modifieConducer(const QPointF &p1, QET::Orientation, const Q
 	// en deduit les coefficients de "redimensionnement"
 	qreal coeff_x = new_dist_2_terminals_x / orig_dist_2_terms_x;
 	qreal coeff_y = new_dist_2_terminals_y / orig_dist_2_terms_y;
-	
+	/*
+	if (!orig_dist_2_terms_x || !orig_dist_2_terms_y) {
+		qDebug() << "ca va planter";
+		PR(coeff_x)
+		PR(coeff_y)
+	}
+	*/
 	// genere les nouveaux points
 	int limite = moves_x.size() - 1;
 	int coeff = type_trajet_x ? 1 : -1;
diff --git a/diagram.cpp b/diagram.cpp
index 495ef5eef..b00d04a0b 100644
--- a/diagram.cpp
+++ b/diagram.cpp
@@ -47,7 +47,7 @@ void Diagram::drawBackground(QPainter *p, const QRectF &r) {
 	p -> setBrush(Qt::white);
 	p -> drawRect(r);
 	
-	if (draw_grid && r.width() < 2500 && r.height() < 2500) {
+	if (draw_grid) {
 		// dessine les points de la grille
 		p -> setPen(Qt::black);
 		p -> setBrush(Qt::NoBrush);
diff --git a/diagramview.cpp b/diagramview.cpp
index 1565ca9f4..ecfb66a51 100644
--- a/diagramview.cpp
+++ b/diagramview.cpp
@@ -222,6 +222,7 @@ void DiagramView::setSelectionMode() {
 */
 void DiagramView::zoomPlus() {
 	scale(4.0/3.0, 4.0/3.0);
+	adjustGridToZoom();
 }
 
 /**
@@ -229,6 +230,7 @@ void DiagramView::zoomPlus() {
 */
 void DiagramView::zoomMoins() {
 	scale(0.75, 0.75);
+	adjustGridToZoom();
 }
 
 /**
@@ -243,6 +245,7 @@ void DiagramView::zoomFit() {
 	}
 	adjustSceneRect();
 	fitInView(sceneRect(), Qt::KeepAspectRatio);
+	adjustGridToZoom();
 }
 
 /**
@@ -250,6 +253,7 @@ void DiagramView::zoomFit() {
 */
 void DiagramView::zoomReset() {
 	resetMatrix();
+	adjustGridToZoom();
 }
 
 /**
@@ -597,3 +601,23 @@ void DiagramView::adjustSceneRect() {
 	// ajuste la sceneRect
 	setSceneRect(elements_bounding_rect.united(border_bounding_rect));
 }
+
+void DiagramView::adjustGridToZoom() {
+	QRectF viewed_scene = viewedSceneRect();
+	scene -> setDisplayGrid(viewed_scene.width() < 2000 || viewed_scene.height() < 2000);
+}
+
+QRectF DiagramView::viewedSceneRect() const {
+	// recupere la taille du widget viewport
+	QSize viewport_size = viewport() -> size();
+	
+	// recupere la transformation viewport -> scene
+	QTransform view_to_scene   = viewportTransform().inverted();
+	
+	// mappe le coin superieur gauche et le coin inferieur droit de la viewport sur la scene
+	QPointF scene_left_top     = view_to_scene.map(QPointF(0.0, 0.0));
+	QPointF scene_right_bottom = view_to_scene.map(QPointF(viewport_size.width(), viewport_size.height()));
+	
+	// en deduit le rectangle visualise par la scene
+	return(QRectF(scene_left_top, scene_right_bottom));
+}
diff --git a/diagramview.h b/diagramview.h
index c732831f4..463c20712 100644
--- a/diagramview.h
+++ b/diagramview.h
@@ -50,6 +50,7 @@ class DiagramView : public QGraphicsView {
 	void dragLeaveEvent(QDragLeaveEvent *);
 	void dragMoveEvent(QDragMoveEvent *);
 	void dropEvent(QDropEvent *);
+	QRectF viewedSceneRect() const;
 	
 	signals:
 	void selectionChanged();
@@ -75,5 +76,6 @@ class DiagramView : public QGraphicsView {
 	private slots:
 	void flushGarbage();
 	void slot_selectionChanged();
+	void adjustGridToZoom();
 };
 #endif