thank you for bringing this up. please make sure that you have the newest version of the addon. the most recent updated does not need a login anymore and is thus even more convenient to use.
thank you - simon
edit: i just saw that you are required to use version 1.8.1 - unfortunately however, google does not provide access to the watch history via their api anymore - i am therefore sorry to say that i have no possibility to bring this feature back into the previous version: https://code.google.com/p/gdata-issues/issues/detail?id=4642#c83
