diff --git a/src/gui/manager.cpp b/src/gui/manager.cpp
index 3e2ab2010..16119d2d8 100644
--- a/src/gui/manager.cpp
+++ b/src/gui/manager.cpp
@@ -1428,12 +1428,11 @@ static Message* new_mouse_msg(int type, JWidget widget)
 
   msg->mouse.x = jmouse_x(0);
   msg->mouse.y = jmouse_y(0);
-  msg->mouse.flags =
-    type == JM_BUTTONRELEASED ? jmouse_b(1):
-				jmouse_b(0);
-  msg->mouse.left = msg->mouse.flags & 1 ? true: false;
-  msg->mouse.right = msg->mouse.flags & 2 ? true: false;
-  msg->mouse.middle = msg->mouse.flags & 4 ? true: false;
+  msg->mouse.flags = (type == JM_BUTTONRELEASED ? jmouse_b(1):
+						  jmouse_b(0));
+  msg->mouse.left = ((jmouse_b(0) & 1) != (jmouse_b(1) & 1));
+  msg->mouse.right = ((jmouse_b(0) & 2) != (jmouse_b(1) & 2));
+  msg->mouse.middle = ((jmouse_b(0) & 4) != (jmouse_b(1) & 4));
 
   if (widget != NULL)
     jmessage_add_dest(msg, widget);
diff --git a/src/tools/tool_loop_manager.cpp b/src/tools/tool_loop_manager.cpp
index 5d93b308f..6cd6819b1 100644
--- a/src/tools/tool_loop_manager.cpp
+++ b/src/tools/tool_loop_manager.cpp
@@ -216,14 +216,18 @@ void ToolLoopManager::snapToGrid(bool flexible, Point& point)
 
 void ToolLoopManager::calculateDirtyArea(ToolLoop* loop, const Points& points, Rect& dirty_area)
 {
-  Point minpt, maxpt;
-  calculateMinMax(points, minpt, maxpt);
+  if (points.size() > 0) {
+    Point minpt, maxpt;
+    calculateMinMax(points, minpt, maxpt);
 
-  // Expand the dirty-area with the pen width
-  Rect r1, r2;
-  loop->getPointShape()->getModifiedArea(loop, minpt.x, minpt.y, r1);
-  loop->getPointShape()->getModifiedArea(loop, maxpt.x, maxpt.y, r2);
-  dirty_area = r1.createUnion(r2);
+    // Expand the dirty-area with the pen width
+    Rect r1, r2;
+    loop->getPointShape()->getModifiedArea(loop, minpt.x, minpt.y, r1);
+    loop->getPointShape()->getModifiedArea(loop, maxpt.x, maxpt.y, r2);
+    dirty_area = r1.createUnion(r2);
+  }
+  else
+    dirty_area = Rect();
 }
 
 void ToolLoopManager::calculateMinMax(const Points& points, Point& minpt, Point& maxpt)