Add this simple directive on input/textarea in your angular app and users won’t be able to drop draggable html5 elements on it.

    app.directive('dropDisable', function() {
    return {
        restrict: 'A',
        link: function(scope, element, attrs) {
            var handler = function(event) {
                event.preventDefault();
                return false;
            }
            element.on('dragenter', handler);
            element.on('dragover', handler);
            element.on('drop', handler);
        }
    };
});

View it in action: