diff --git a/skimage/viewer/canvastools/linetool.py b/skimage/viewer/canvastools/linetool.py
index 0b6de5a4..6dbda97b 100644
--- a/skimage/viewer/canvastools/linetool.py
+++ b/skimage/viewer/canvastools/linetool.py
@@ -75,6 +75,7 @@ class LineTool(CanvasToolBase):
 
         self._line.set_data(np.transpose(pts))
         self._handles.set_data(np.transpose(pts))
+        self._line.set_linewidth(self.linewidth)
 
         self.set_visible(True)
         self.redraw()
diff --git a/skimage/viewer/viewers/core.py b/skimage/viewer/viewers/core.py
index 52e2259f..f1e541a1 100644
--- a/skimage/viewer/viewers/core.py
+++ b/skimage/viewer/viewers/core.py
@@ -83,6 +83,7 @@ class EventManager(object):
         self.connect_event('key_press_event', self.on_key_press)
         self.connect_event('button_release_event', self.on_mouse_release)
         self.connect_event('motion_notify_event', self.on_move)
+        self.connect_event('scroll_event', self.on_scroll)
 
         self.tools = []
         self.active_tool = None
@@ -128,6 +129,11 @@ class EventManager(object):
         if not tool is None:
             tool.on_move(event)
 
+    def on_scroll(self, event):
+        tool = self._get_tool(event)
+        if not tool is None:
+            tool.on_scroll(event)
+
 
 class ImageViewer(QtGui.QMainWindow):
     """Viewer for displaying images.