Ticket #5926: 5926.patch

_source/plugins/clipboard/plugin.js

@@ -393 +393 @@
                                                                 cut : !readOnly && stateFromNamedCommand( 'Cut' ),
 
                                                                 // Browser bug: 'Cut' has the correct states for both Copy and Cut.
-                                                                copy : stateFromNamedCommand( 'Cut' ),
+                                                                // In IE and Chrome the command is always off inside readOnly element, so we have to check it manually (#5926)
+                                                                copy : stateFromNamedCommand( 'Cut' ) || ( readOnly && !selection.getRanges()[0].collapsed ),
                                                                 paste : !readOnly && ( CKEDITOR.env.webkit ? CKEDITOR.TRISTATE_OFF : stateFromNamedCommand( 'Paste' ) )
                                                         };
                                                 });