Highlights get overwritten #458

Using latest Development branch,
Also happens in 1.12.0
How to recreate:

1. Import highlights,json , you'll see the file [appdata]\LogExpert\settings.json gets bigger with the added data.
2. Close the application
3. Open the application
4. Open a text log file in a network drive, (not sure network is related)
5. Close the application.
6. Goto step 3 until the file [appdata]\LogExpert\settings.json reverts back with all the highlights data lost