deleting test data folders or resource files without deleting resource imports leave corresponding keywords highlighted

[yanne]

Originally submitted to Google Code by @kontulai on 27 Aug 2012

Steps to reproduce:

1. open test folder
2. create suite and resource file (or folder with tests and resource file there)
3. create kw to resource file
4. import resource file to suite
5. create test case or user keyword in suite and use keyword from resource file in it
6. delete resource file (or folder that contains resource file) WITHOUT "Also delete resource imports" selected
7. go to test case or user keyword. the keyword from deleted resource is still highlighted even though the resource is not available.

[HelioGuilherme66]

This issue is still observable on 1.7.4.1dev0, Windows10, wxPython 4.0.7post2 and Python 2.7.16.