My 2 cents to that topic:
There seems to be an error in Booking.php in line 133:
if (setting('default_language') != 'en')
$this->addJs('vendor/datepicker/bootstrap-datepicker/locales/bootstrap-datepicker.'.strtolower(str_replace('_', '-', setting('default_language'))).'.min.js', 'bootstrap-datepicker-js');
I assume the path to the datapicker-script is wrong. I ’ve to change it to:
$this->addJs('~/app/admin/formwidgets/datepicker/assets/vendor/datepicker/locales/bootstrap-datepicker.'.strtolower(str_replace('_', '-', setting('default_language'))).'.min.js', 'bootstrap-datepicker-js');
And an other hint:
If you create your own language and insert a locale code (en, fr, etc) the comment says:
Use a full locale code (e.g. “fr_FR”) instead of just a generic language code (e.g. “fr”), must be same as the locale directory.
In my own words: if I use a locale code like fr it is wrong and if I use a locale code like fr_FR it is correct.
BUT … !
… if you do so, the line above generates a datapicker-filename like bootstrap-datepicker.fr-fr.min.js
. And this file dosnt exist!
So, you have to set the locale code to the short version like fr. (And dont forget to change your path on the filesystem - and maybe you have to reset your default language)
That works for me.
Or did I misunderstood something in general?