Sync changes with all opened tabs

- [x] I am running the latest version
- [x] I checked the documentation and found no answer
- [x] I checked to make sure that this issue has not already been filed

Problem Description
- Modify DNS server addresses or write, change custom filtering rules and close the tab. If you have any other tabs opened and mistakenly press save button or if you add (or remove) new DNS servers, custom filtering rules and save it. You'll loss previous tab made all changes
- Enable or disable settings changes don't effect on other tabs