--- a/ProjectController.py	Thu Oct 20 14:45:27 2016 +0300
+++ b/ProjectController.py	Fri Oct 21 13:06:31 2016 +0300
@@ -1119,6 +1119,7 @@
                 self._IECCodeView = IECCodeViewer(self.AppFrame.TabsOpened, "", self.AppFrame, None, instancepath=name)
                 self._IECCodeView.SetTextSyntax("ALL")
                 self._IECCodeView.SetKeywords(IEC_KEYWORDS)
+                self._IECCodeView.Editor.SetReadOnly(True)                
                 try:
                     text = file(plc_file).read()
                 except:

--- a/editors/TextViewer.py	Thu Oct 20 14:45:27 2016 +0300
+++ b/editors/TextViewer.py	Fri Oct 21 13:06:31 2016 +0300
@@ -908,7 +908,7 @@
                         key_handled = True
             if not key_handled:
                 event.Skip()
-        elif key in NAVIGATION_KEYS:
+        else:
             event.Skip()
 
     def OnKillFocus(self, event):