Problem with multiple select removing more than 1 option

It's easiest to do this with jQuery but it you want to do this using plain Javascript you can.

The problem you are experiencing is that when you remove an item from the options list in Opera it deselects all the selected items, so only the first is removed. A workaround is to first remember which items were selected before removing any.

var action_list = document.getElementById("actions_list");

// Remember selected items.
var is_selected = [];
for (var i = 0; i < action_list.options.length; ++i)
{
    is_selected[i] = action_list.options[i].selected;
}

// Remove selected items.
i = action_list.options.length;
while (i--)
{
    if (is_selected[i])
    {
        action_list.remove(i);
    }
}

You can do it much easier using jQuery:

$('#actions_list option:selected').remove()