Just hit this. You can find the location in localstore.rdf where sizemode="fullscreen", and set it back to "normal", which (other than deleting the file entirely) seems to be the only way to address this in thunderbird.
Just hit this. You can find the location in localstore.rdf where sizemode= "fullscreen" , and set it back to "normal", which (other than deleting the file entirely) seems to be the only way to address this in thunderbird.