Having used GWT in the past, the GWT error makes sense. When loading a GWT application, GWT first sniffs the user agent and locale. It then downloads a differen

Having used GWT in the past, the GWT error makes sense. When loading a GWT application, GWT first sniffs the user agent and locale. It then downloads a different javascript file, optimized for the given user agent and locale. For example, the javascript file served to a French user using Firefox will contain only French labels, and won't contain any code to deal with IE, Chrome... User agent sniffing is not always good practice, but, in this case, it results in a nice performance improvement :) You can even use it to have a "production" and a "debug" version of your app. By adding "?debug=true" to your URL, GWT would load the "debug" version, which could for example contain code to log information. https://developers.google.com/web-toolkit/doc/latest/FAQ_DebuggingAndCompiling https://developers.google.com/web-toolkit/doc/latest/FAQ_Deb...