Error messages LnF

<accesscontrol>Main:MyGroup</accesscontrol> Error messages LnF

1. Error messages should always explain exactly what the user did wrong. If user cannot immediately understand what the message means; it is a bug!
2. If the same error message is used for two different bugs - it is a bug!
3. Errors should appear in the top of dialogues / windows in red color in bullet format. All the errors that are registered should be listed.
4. The title of dialog must be "Error" if the message lets users know that they can NOT do that action. And "Warning" if still allowing users to continue that action.
5. The GUI should not refresh before showing the errors (if possible)