This occurs with retina, and possibly other themes, and is a result of the themes input styling affecting the styling of the input tags in the builder widget. All that needs to be done to fix this is add the following CSS to the theme's CSS file:
.search_bar select, .search_bar input {
display: inline !important;
}
The theme may affect the width and padding of the input fields as well, so something like this may fix it:
.main_search_label {
width: auto !important;
}
.search_bar #within_distance {
width: 90px !important;
}
.search_bar #limit {
width: 62px !important;
}