Hi Claudio, you need to modify a line in the file
/modules/mod_floating_buttons/tmpl/default.php
Find this line (line 17):
<ul id="options<?php echo $module->id; ?>" class="options-list">
Change it to:
<ul id="options<?php echo $module->id; ?>" class="options-list active" style="display: block;">
You can also do that via a template override, please see this video if you want to do that: