simplify logic

GUI/View/Mask/MaskGraphicsScene.cpp

@@ -254,23 +254,17 @@ void MaskGraphicsScene::mousePressEvent(QGraphicsSceneMouseEvent* event)
             makeViewAtMousePosSelected(event);
         return;
     }
-    if (isValidForPolygonDrawing(event)) {
+
+    if (isValidForPolygonDrawing(event))
         processPolygonItem(event);
-        return;
-    }
-    if (isValidForLineDrawing(event)) {
+    else if (isValidForLineDrawing(event))
         processLineItem(event);
-        return;
-    }
-    if (isValidForMaskAllDrawing(event)) {
+    else if (isValidForMaskAllDrawing(event))
         processMaskAllItem(event);
-        return;
-    }
-    if (isValidForRectangleShapeDrawing(event)) {
+    else if (isValidForRectangleShapeDrawing(event))
         processRectangleOrEllipseItem(event);
-        return;
-    }
-    QGraphicsScene::mousePressEvent(event);
+    else
+	QGraphicsScene::mousePressEvent(event);
 }
 
 void MaskGraphicsScene::mouseMoveEvent(QGraphicsSceneMouseEvent* event)