Reply To: submit button needs double click

I purchased Premium yesterday (v3.2.4) I have the same issue: User requires a double click on the submit button

Some configuration I made to the out-of-the box settings:

Since I organize events on one day,
– I enabled one-click selection (of the ‘arival’ date) in the calendar by adding the select=”1″ to [easy calendar], by the way this only works when you place the ‘select’ attribute as the last attribute
– I don’t need the [date-to] info so put the [hidden date-to ..] in the form; unfortunately [date-to] does play a role in the background as the reservation is shown in the overview as starting May29 and ending May30, where I like them to have the same date; any suggestion on this side question?
– resource called Event, pay per person, availability based upon person

Any secret attribute I need to add to [submit] ?