First dropdown inside the model opens after the modal is shown
see the pen: https://codepen.io/lackneets/pen/LyBwEK
Sorry I found it caused by autofocus option.
Realmente pasa por la opcion showOnFocus del dropdown
https://semantic-ui.com/modules/dropdown.html#/settings
$('.ui.dropdown').dropdown({
showOnFocus:false
});
Most helpful comment
Sorry I found it caused by autofocus option.