Merge remote branch 'upstream/develop-next' into 1.12.x

account.php

css/jquery-ui-timepicker-addon.css

include/ajax.thread.php

include/class.charset.php

include/class.dept.php

include/class.dynamic_forms.php

include/class.export.php

include/class.file.php

include/class.format.php

include/class.forms.php

include/class.list.php

include/class.mailfetch.php

include/class.misc.php

include/class.search.php

include/class.task.php

include/class.thread.php

include/class.thread_actions.php

include/class.ticket.php

include/class.user.php

include/class.validator.php