Share de-selects the single site criteria and selects All Sites to run the second search

When in a Share Site if a simple search is performed it takes you to the results page and if another search is performed before the original search has completed it de-selects the single site criteria and selects All Sites to run the second search.

Reproduction Steps

1) Install Alfresco (4.1.7.3 installer - basic install)
2) Switch from SOLR to Lucene (Not sure if this is required for reproduction but to force the searches to take longer to return results I went this route).
3) Create a Site named Test into Alfresco
4) Load Site Test with a lot of content (I did roughly 10,000 folders in a 3 level structure with around 4 million documents). In Place import was used to load documents.
5) Access the Site Test and search for content
6) The page should re-direct now to the search page and the Site Name should be highlighted above the search field (Test Site) and in the results section is should state "Searching"
7) While no results have been found and it still states "Searching" erase the previous search text and search again
8) The Highlighted search area should change from the site name(Test Site) to "All Sites" and the new search is performed against that instead of the individual site.

Customer has reproduced this behavior on 4.1.4, 4.1.7.3, and I have reproduced using 4.2.1.

(Trevor Hines reproduced)