in the orders list view you can call the mail client clicking the e-mail address in the list. mayby sometimes you need to do it from orders detail view? the solution: find the line: <input type="text" name="sEmail" value="$aData[sEmail]" size="50" maxlength="40" class="input" alt="email"/> in templates/admin/order.tpl and replace it with: <input type="text" name="sEmail" value="$aData[sEmail]" size="50" maxlength="40" class="input" alt="email" ondblclick="window.location.href='mailto:$aData[sEmail]'+'?subject=$lang[Order] nr: $aData[iOrder] '+'additional text in subject line';"/>
i chose the doubleclick to prevent opening the mail client by single click (sometimes needed if corrections are to do).
now, with double click on e-mail field, the mail client will be opened with filled addres line (customers) and subject - in this example: "Order nr: X additional text in subject line"
