The user of-course can already implicitly work out this information from comparing the fee-rate with the actual fee.

I think that it would be useful for people not wanting to do this arithmetic in their head.

strHTML += "<ul>";
        BOOST_FOREACH(const CTxIn& txin, wtx.vin)
        {
            COutPoint prevout = txin.prevout;
            CCoins prev;
            if(pcoinsTip->GetCoins(prevout.hash, prev))
            {
                if (prevout.n < prev.vout.size())
                {
                    strHTML += "<li>";
                    const CTxOut &vout = prev.vout[prevout.n];
                    CTxDestination address;
                    if (ExtractDestination(vout.scriptPubKey, address))
                    {
                        if (wallet->mapAddressBook.count(address) && !wallet->mapAddressBook[address].name.empty())
                            strHTML += GUIUtil::HtmlEscape(wallet->mapAddressBook[address].name) + " ";
                        strHTML += QString::fromStdString(CBitcoinAddress(address).ToString());
                    }
                    strHTML = strHTML + " " + tr("Amount") + "=" + BitcoinUnits::formatHtmlWithUnit(unit, vout.nValue);
                    strHTML = strHTML + " IsMine=" + (wallet->IsMine(vout) & ISMINE_SPENDABLE ? tr("true") : tr("false")) + "</li>";
                    strHTML = strHTML + " IsWatchOnly=" + (wallet->IsMine(vout) & ISMINE_WATCH_ONLY ? tr("true") : tr("false")) + "</li>";
                }
            }
        }
        strHTML += "</ul>";
    }
    strHTML += "</font></html>";
    return strHTML;
}