After an (involuntary) update "save page to" Ctrl-S shows a new inconvenient behaviour

It seems that a few days ago my Firefox was (involuntarily) updated in the course of another update (Linux): Previously, after Ctrl-S I could immediately start editing the name of the downloaded .html file, usually replacing it: the .html was retained, but the main part was highlighted and replaced automatically with the first typed character. Now one has to highlight the name with "select all" and also take care of the .html suffix. This is highly inconvenient if one wants to change the (usually) much too long names. Is there a chance (option?) to get the old behaviour back? (By the way, not connected with this change: It is annoying that Firefox silently changes `:` to `_´ in desired names though these are perfectly legal in Linux.) (and I would like to be able to use Firefox save to command from the command line.