Undefined Variable Notice in Views UI

Hello,

Im creating a block view, with the 'charts' display.

Ive got an error which look like this :

Notice : Undefined variable: selected_fields dans track_field_changes_handler_filter_field_info->get_value_options() (ligne 19 dans sites\all\modules\track_field_changes\views\track_field_changes_handler_filter_field_info.inc).

This error is displayed multiple times on top of my view configuration, and I cant make it work ...

Ive already selected my node type to track. And checked "Track field changes for updated node " than checked the filed I want to track.

I don't know if its a bug or if this a configuration/incompatibility problem,

What do you think ?