Never Trust the Space Tab Rogue Extension
Space Tab is the name of a rogue browser extension that behaves like a browser hijacker.
Upon being added to your browser, Space Tab will make a number of unwanted changes to your browser. First and foremost it will change your browser's default search engine to find dot gsearchwithus dot com. This is a fake search engine that will not produce reliable results.
In addition to this, fake search engines may collect data on your browsing habits and your search queries. This data is commonly shared with and resold to third parties, usually advertising agencies that can use this data to better target ads.
Finally, fake search engines of this kind may populate their results pages with bad redirects and links to sponsored content that may be completely irrelevant to your search query. In the case of this specific search engine, it simply funnels your search through Bing and produces a Bing results page.
If you find Space Tab in your browser, you would do well to remove it and restore your browser to its previous settings.