diff --git a/skimage/io/__init__.py b/skimage/io/__init__.py
index a485250e..d0ec1f43 100644
--- a/skimage/io/__init__.py
+++ b/skimage/io/__init__.py
@@ -26,7 +26,7 @@ def _format_plugin_info_table(info_table, column_lengths):
     info_table.insert(0, _separator('=', column_lengths))
     info_table.insert(1, ('Plugin', 'Description'))
     info_table.insert(2, _separator('-', column_lengths))
-    info_table.append(_separator('-', column_lengths))
+    info_table.append(_separator('=', column_lengths))
 
 
 def _update_doc(doc):
diff --git a/skimage/viewer/plugins/base.py b/skimage/viewer/plugins/base.py
index 6b162fd8..def0bfd9 100644
--- a/skimage/viewer/plugins/base.py
+++ b/skimage/viewer/plugins/base.py
@@ -142,7 +142,7 @@ class Plugin(QtGui.QDialog):
             plugin += Widget(...)
 
         Widgets can adjust required or optional arguments of filter function or
-        parameters for the plugin. This is specified by the Widget's `ptype'.
+        parameters for the plugin. This is specified by the Widget's `ptype`.
         """
         if widget.ptype == 'kwarg':
             name = widget.name.replace(' ', '_')
diff --git a/skimage/viewer/plugins/color_histogram.py b/skimage/viewer/plugins/color_histogram.py
index 99205c41..52c71786 100644
--- a/skimage/viewer/plugins/color_histogram.py
+++ b/skimage/viewer/plugins/color_histogram.py
@@ -73,14 +73,16 @@ class ColorHistogram(PlotPlugin):
             The selected pixels.
         data : dict
             The data describing the histogram and the selected region.
-            Keys:
-                - 'bins' : array of float, the bin boundaries for both
-                    `a` and `b` channels.
-                - 'hist' : 2D array of float, the normalized histogram.
-                - 'edges' : tuple of array of float, the bin edges
-                    along each dimension
-                - 'extents' : tuple of float, the left and right and
-                    top and bottom of the selected region.
+            The dictionary contains:
+
+              - 'bins' : array of float
+                The bin boundaries for both `a` and `b` channels.
+              - 'hist' : 2D array of float
+                The normalized histogram.
+              - 'edges' : tuple of array of float
+                The bin edges along each dimension
+              - 'extents' : tuple of float
+                The left and right and top and bottom of the selected region.
         """
         return (self.mask, self.data)