diff --git a/Lib/idlelib/idle_test/test_help_about.py b/Lib/idlelib/idle_test/test_help_about.py
new file mode 100644
index 00000000000..d0a012767a8
--- /dev/null
+++ b/Lib/idlelib/idle_test/test_help_about.py
@@ -0,0 +1,52 @@
+'''Test idlelib.help_about.
+
+Coverage:
+'''
+from idlelib import aboutDialog as help_about
+from idlelib import textView as textview
+from idlelib.idle_test.mock_idle import Func
+from idlelib.idle_test.mock_tk import Mbox
+import unittest
+
+About = help_about.AboutDialog
+class Dummy_about_dialog():
+    # Dummy class for testing file display functions.
+    idle_credits = About.ShowIDLECredits
+    idle_readme = About.ShowIDLEAbout
+    idle_news = About.ShowIDLENEWS
+    # Called by the above
+    display_file_text = About.display_file_text
+
+
+class DisplayFileTest(unittest.TestCase):
+    "Test that .txt files are found and properly decoded."
+    dialog = Dummy_about_dialog()
+
+    @classmethod
+    def setUpClass(cls):
+        cls.orig_mbox = textview.tkMessageBox
+        cls.orig_view = textview.view_text
+        cls.mbox = Mbox()
+        cls.view = Func()
+        textview.tkMessageBox = cls.mbox
+        textview.view_text = cls.view
+        cls.About = Dummy_about_dialog()
+
+    @classmethod
+    def tearDownClass(cls):
+        textview.tkMessageBox = cls.orig_mbox
+        textview.view_text = cls.orig_view
+
+    def test_file_isplay(self):
+        for handler in (self.dialog.idle_credits,
+                        self.dialog.idle_readme,
+                        self.dialog.idle_news):
+            self.mbox.showerror.message = ''
+            self.view.called = False
+            handler()
+            self.assertEqual(self.mbox.showerror.message, '')
+            self.assertEqual(self.view.called, True)
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)
diff --git a/Lib/idlelib/idle_test/test_textview.py b/Lib/idlelib/idle_test/test_textview.py
index 764a1a5e1b0..0c625eefe90 100644
--- a/Lib/idlelib/idle_test/test_textview.py
+++ b/Lib/idlelib/idle_test/test_textview.py
@@ -5,7 +5,7 @@
 Using mock Text would not change this.  Other mocks are used to retrieve
 information about calls.
 
-The coverage is essentially 100%.
+Coverage: 94%.
 '''
 from idlelib import textview as tv
 from test.support import requires
@@ -15,7 +15,7 @@
 import os
 from tkinter import Tk
 from idlelib.idle_test.mock_idle import Func
-from idlelib.idle_test.mock_tk import Mbox
+from idlelib.idle_test.mock_tk import Mbox_func
 
 def setUpModule():
     global root
@@ -64,17 +64,17 @@ def test_ok(self):
         view.destroy
 
 
-class textviewTest(unittest.TestCase):
+class ViewFunctionTest(unittest.TestCase):
 
     @classmethod
     def setUpClass(cls):
-        cls.orig_mbox = tv.tkMessageBox
-        tv.tkMessageBox = Mbox
+        cls.orig_error = tv.showerror
+        tv.showerror = Mbox_func()
 
     @classmethod
     def tearDownClass(cls):
-        tv.tkMessageBox = cls.orig_mbox
-        del cls.orig_mbox
+        tv.showerror = cls.orig_error
+        del cls.orig_error
 
     def test_view_text(self):
         # If modal True, tkinter will error with 'can't invoke "event" command'
@@ -89,7 +89,7 @@ def test_view_file(self):
         self.assertIn('Test', view.textView.get('1.0', '1.end'))
         view.Ok()
 
-        # Mock messagebox will be used and view_file will not return anything
+        # Mock showerror will be used and view_file will return None
         testfile = os.path.join(test_dir, '../notthere.py')
         view = tv.view_file(root, 'Title', testfile, modal=False)
         self.assertIsNone(view)
diff --git a/Lib/idlelib/textView.py b/Lib/idlelib/textView.py
index 9dc83574ee6..b9ca9e3269d 100644
--- a/Lib/idlelib/textView.py
+++ b/Lib/idlelib/textView.py
@@ -77,6 +77,10 @@ def view_file(parent, title, filename, encoding=None, modal=True):
         tkMessageBox.showerror(title='File Load Error',
                                message='Unable to load file %r .' % filename,
                                parent=parent)
+    except UnicodeDecodeError as err:
+        tkMessageBox.showerror(title='Unicode Decode Error',
+                               message=str(err),
+                               parent=parent)
     else:
         return view_text(parent, title, contents, modal)