Dropdown options problem

All the dropboxes it is with a problem as is follow.

For exemple, when I click in the dropbox to change the range of the days in the Dashboard page, the list of options blink once and the arrow change from down to up, but it´s impossibile to click in one of the options.
Result in the impossibilty to change anything configuration in the plugin.

Thanks

The page I need help with: [log in to see the link]