GWT Exception in Storage.isSupported()

Question

I am struggling with a GWT problem that suddenly occurred in a component of my app that I didn't even touch.

I get an Operation is not supported exception in the 2nd line of Storage.isSupported(), a function of GWT implementing the W3C's HTML5 storage specification:

function Storage$StorageSupportDetector_0(){
    this.isLocalStorageSupported = typeof $wnd.localStorage != 'undefined';
    this.isSessionStorageSupported = typeof $wnd.sessionStorage != 'undefined';
} 

This is really perplexing, because it's all GWT internal stuff. The above function is generated by GWT from GWT's own code. Plus: The problem occurs only in production mode. In development mode, everything works fine.

I am using plain GWT 2.4 (the latest) and no additional libraries. The problem is not browser-specific (I tried them all).

Any ideas would be greatly appreciated. Please answer also if you don't know the concrete solution, but have a tip on how I could approach this problem in general.

Thanks!

Answer 1

After hours of research, and carefully composing the above question, I found this:

Error using sessionStorage

In short, Session Storage does not work if you loaded the page from file:. Oh well.

(We might still want to keep this question around because it might enable people to find the solution by searching for the function code I posted.)