Ok, I give an asnwer to myself. This is something coming from bootstrap 3 bug. Simply add the following into your CSS file

.bookingTip {
display: inline !important;
}

et voilà :-)

Hello,

I am trying the free version of Booking prior to buy it. Things are going well except when I want to see "tips" on several labels in front end. When mouse is hover the tips popup is displaying and when mouse leaves the area the popup disappears (that's good) but the label as well (style "display:none" is applied on it). This is for example on the booking calendar page where prices and accomodations labels shows tips.

Any recommendation where the problem is coming from ?

Regards,