JSFiddle - React, Tailwind, and code Playground

HTML

<div class='report_info'>
<select name="DropDownList1" id="DropDownList1">
	<option value="1">1</option>
	<option value="2">2</option>
	<option value="3">3</option>
	<option value="4">4</option>
</select>
</div>
<div class='report_info'>
<select name="DropDownList2" id="DropDownList2">
	<option value="1">1</option>
	<option value="2">2</option>
	<option value="3">3</option>
	<option value="4">4</option>
</select>
</div>
<div class='report_info'>
<select name="DropDownList3" id="DropDownList3">
	<option value="1">1</option>
	<option value="2">2</option>
	<option value="3">3</option>
	<option value="4">4</option>
</select>
</div>
<div class='report_info'>
<select name="DropDownList4" id="DropDownList4">
	<option value="1">1</option>
	<option value="2">2</option>
	<option value="3">3</option>
	<option value="4">4</option>
</select>
</div>

JavaScript

var shifted = false;

$(document).on('keyup keydown', function (e) { shifted = e.shiftKey });

$(document).on('keyup keydown', 'select', function (e) {
    shifted = e.shiftKey;
});

    $(document).on('change', '.report_info select', function (e) {
        var cr = $(this).val();
        if (shifted) {
            $('.report_info select').each(function () {
                $(this).val(cr);
            });
        }
    });