diff --git a/spyderlib/plugins/inspector.py b/spyderlib/plugins/inspector.py
index <HASH>..<HASH> 100644
--- a/spyderlib/plugins/inspector.py
+++ b/spyderlib/plugins/inspector.py
@@ -335,5 +335,9 @@ class ObjectInspector(ReadOnlyEditor):
                 is_code = True

         self.editor.set_highlight_current_line(is_code)

         self.editor.set_occurence_highlighting(is_code)

+        if is_code:

+            self.editor.set_language('py')

+        else:

+            self.editor.set_language(None)

         self.editor.set_text(hlp_text)

         self.editor.set_cursor_position('sof')

diff --git a/spyderlib/widgets/codeeditor/codeeditor.py b/spyderlib/widgets/codeeditor/codeeditor.py
index <HASH>..<HASH> 100644
--- a/spyderlib/widgets/codeeditor/codeeditor.py
+++ b/spyderlib/widgets/codeeditor/codeeditor.py
@@ -304,7 +304,12 @@ class CodeEditor(TextEditBaseWidget):
         self.tab_indents = language in self.TAB_ALWAYS_INDENTS

         self.supported_language = False

         self.comment_string = ''

-        if language is not None:

+        if language is None:

+            if self.highlighter is not None:

+                self.highlighter.setDocument(None)

+            self.highlighter = None

+            self.highlighter_class = None

+        else:

             for key in self.LANGUAGES:

                 if language.lower() in key:

                     self.supported_language = True
Fixed Issue <I>: don't do syntax highlighting in the "Object Inspector" when not showing the source