When this extension is turned on, it will block the opening of new tabs or new windows, especially those that are not intended by the user, and those that led to unwanted advertisements. This will reduce the annoyance of having to find and close the new tab or window that is opened, especially when a new window is opened on the bottom right corner of your screen.
When this extension is turned off, browser actions resume to normal, new tabs are allowed, new windows are allowed.