In Autumn 2003, the inventor of the World Wide Web and the Director of the W3C Consortium Tim Berners-Lee wrote to Under Secretary of Commerce, asking to invalidate this patent, in order to "eliminate this major impediment to the operation of the Web". Leaders of Open Source Community sided with Microsoft in fighting the patent due to its threat to the free nature of the Web and to the basic established HTML standards. The specific concerns of having one company (Eolas) controlling a critical piece of the Web framework were cited.
In March 2004, the United States Patent and Trademark Office (USPTO) re-examined and initially rejected the patent. Eolas submitted a rebuttal in May 2004. On September 27, 2005, the USPTO upheld the validity of the patent. The PTO ruling rejected the relevance of Pei Wei's Viola code to the Eolas patent. According to the University of California press release, "In its 'Reasons for Patentability/Confirmation' notice, the patent examiner rejected the arguments for voiding UC's previously approved patent claims for the Web-browser technology as well as the evidence presented to suggest that the technology had been developed prior to the UC innovation. The examiner considered the Viola reference the primary reference asserted by Microsoft at trial as a prior art publication and found that Viola does 'not teach nor fairly suggest that instant 906 invention, as claimed.'
In 1999 Eolas filed suit in the US District Court for the Northern District of Illinois against Microsoft over validity and use of the patent. Eolas won the initial case in August 2003 and was awarded damages of $521m from Microsoft for infringement. The District Court reaffirmed the jury's decision in January 2004.
In June 2004 Microsoft appealed the case to the Court of Appeals for the Federal Circuit. In March 2005 the District Court judgment was remanded, but the infringement and damages parts of the case were upheld. The appeals court ruled that the two Viola-related exhibits that had been thrown out of the original trial needed to be shown to a jury in a retrial. Microsoft quickly filed for a rehearing.
In October 2005, The Supreme Court of the United States refused to hear Microsoft's appeal, leaving intact the Federal Circuit Court of Appeals ruling in favor of Eolas with respect to foreign sales of Microsoft Windows. However, the remand to District Court had not been heard yet.
In May 2007 the USPTO agreed to allow Microsoft to argue ownership of the patent after they reissued a Microsoft patent that covers the same concepts as outlined in the Eolas patent, and contains wording that mirrors the Eolas patent. The USPTO ruled in favor of Eolas on that matter in September 2007.
Microsoft and Eolas agreed in July 2007 to delay a pending re-trial, in order to negotiate a settlement. On August 27, 2007, Eolas reported to its shareholders that a settlement had been reached, and that Eolas expected to pay a substantial dividend as a result; the exact amount and terms of the settlement were not disclosed.
In February, 2006 Microsoft modified its Internet Explorer web browser to appear to side-step the Eolas patent. The change, first discussed in 2003 , requires users to click once on an ActiveX control to "activate" it before they can use its interface. The specific message is "Click to activate this control", shown as a tooltip when the cursor is held over the embedded object. However, following a November 2007 announcement that Microsoft had "licensed the technologies from Eolas" , in April 2008 Microsoft released an update which removed the click to activate functionality reverting the software to its original design.
Other browsers such as Mozilla Firefox and Apple's Safari might feel they have to implement a similar change to attempt to avoid infringement, or to license Eolas' patent. Dr. Doyle has stated that Eolas would offer royalty-free licenses to non-commercial entities. A statement on Eolas' web site clarifies the company's policy with regard to such licenses. Eolas has not yet indicated intent to pursue further cases As of 2007, no Eolas license has been granted to the leading open-source browser, Mozilla Firefox. Eolas itself never made a popular web-browser product utilizing its patent, which led many to use it as an example of a patent troll. Nevertheless, Eolas did release a historically-significant version of its browser, called WebRouser, for noncommercial use in 1995.