Comment 2 for bug 1773450

When testing another bug in the reporter (in Ben´s 3.2 beta sandbox), I have found funny thing. The part of the legacy interface (particularly names of the folders and some messages in the pop-up windows) were displayed in the Czech language even when I was using English interface at the moment (see the attachment). I tried to clear both the cache and the cookies because had switched from Czech to English (and vice versa) previously. Still, the interface remained in the Czech language after clearing cookies and cache.
I installed the Opera browser, that I was quite sure had never been used on the given workstation, to exclude the influence of some previous language settings in the browser. again, the part of the interface mentioned above remained in the Czech language even in English locale.
I am still not sure if this behavior is not any coincidence, however, I wonder if this could not be related to the language settings of the operating system (which was Czech on the workstation where I tested the reporter).