Hi Colin, absolutely understand what you say and agree that is not a GXT issue. For the moment, just lets keep the thread open as we both agree that is an interesting idea and having GXT extensions in Chrome can be really great (https://chrome.google.com/webstore/category/extensions). As commented I just started with extensions so I do not have enough knowledge to solve the issue yet. But I will update the thread when I learn more or maybe somebody else. For the moment, just wanted to understand what other people was doing on this and if there was a solution already known by the community.
(PS: I did not use the zip file. Instead, I deployed a new GWT with Eclipse and it creates the demo project itself)