Prevents duplicate tabs
The Prevent Duplicate Tabs extension for the Chrome web browser will prevent two tabs with the same URL from opening. If a new tab is opened with an URL that is opened in another tab, the old tab will be closed and the requested URL will be opened in a new tab.
This extension was developed to fix an annoyance that occurs in Eclipse based editors like Aptana, Flex Builder or stand-alone Eclipse, where clicking on the Run/Build/Debug buttons (or menu items) will always open the project in a new browser window or tab. The annoyance is that it is very easy to end up with many tabs opened to the same URL.
To use the extension, simply navigate to the page that you wish to have no duplicate open tabs of. Click on the small "tab" icon near the location bar. The tab icon will now have a red blocker icon indicating that the page will no longer open with duplicate tabs. Clicking on the icon again would remove the page from the duplicate tab whitelist.