Events tpl. the drop down based on RB is displayed but unused

Cedric created a tag to display in a jahia page a list coming from a llocal RB file, this one is positionned in the events template but not integrated in the search or sorting filters

Pb 1 : the tag displays only the list based on RB, so in a dropdown there is no label like "sort by event type". How to solve this issue ?
Pb2 (linked to 1) : if the form associated with the dropdown list is validated using a js, then the first element of the list is selected by default, meaning that you must choose another one, before beeing able to select the first and make your sort on it.