In server/patron/, summary_overlay.xul summary_overlay_horiz.xul and bills_overlay.xul, take every element that has class="hide_patron_credit" and change hidden="true" to hidden="false". Also, in bills_overlay.xul, look for id="payment_type_menuitem4", and uncomment that element. The thought, which we never finished implementing, was to move away from the @hidden attribute, and set up some CSS to look for the hide_patron_credit class. Then folks could use local CSS to override the behavior for hide_patron_credit.
<row id="pdsgr2" class="hide_patron_credit" hidden="true">
<label id="PatronSummaryStatus_credit_label" class="text_left credit label"
value="&staff.patron_display.credit.label;" />
<label id="patron_credit" class="credit value"/>
</row><row>
becomes
<row id="pdsgr2" class="hide_patron_credit" hidden="false">
<label id="PatronSummaryStatus_credit_label" class="text_left credit label"
value="&staff.patron_display.credit.label;" />
<label id="patron_credit" class="credit value"/>
</row><row>
<row class="hide_patron_credit" hidden="true">
<label value="&staff.patron.bills_overlay.patron_credit.value;"
style="font-family: bold" />
<textbox id="bill_credit_amount" readonly="true" context="clipboard"/>
</row>
becomes
<row class="hide_patron_credit" hidden="false">
<label value="&staff.patron.bills_overlay.patron_credit.value;"
style="font-family: bold" />
<textbox id="bill_credit_amount" readonly="true" context="clipboard"/>
</row>
and
<button class="hide_patron_credit" hidden="true" disabled="true" id="change_to_credit" label="&staff.patron.bills_overlay.convert_change_to_credit.label;" command="cmd_change_to_credit"/>
becomes
<button class="hide_patron_credit" hidden="false" disabled="true" id="change_to_credit" label="&staff.patron.bills_overlay.convert_change_to_credit.label;" command="cmd_change_to_credit"/>
and
<menulist id="payment_type">
<menupopup id="payment_type_menupopup">
<menuitem id="payment_type_menuitem1" label="&staff.patron.bills_overlay.cash.label;" value="cash_payment"/>
<menuitem id="payment_type_menuitem2" label="&staff.patron.bills_overlay.check.label;" value="check_payment"/>
<menuitem id="payment_type_menuitem3" label="&staff.patron.bills_overlay.credit_card.label;" value="credit_card_payment"/>
<!--
<menuitem id="payment_type_menuitem4" label="Patron Credit" value="credit_payment" />
-->
<menuitem id="payment_type_menuitem5" label="&staff.patron.bills_overlay.word.label;" value="work_payment"/>
<menuitem id="payment_type_menuitem6" label="&staff.patron.bills_overlay.forgive.label;" value="forgive_payment"/>
<menuitem id="payment_type_menuitem7" label="&staff.patron.bills_overlay.goods.label;" value="goods_payment"/>
</menupopup>
</menulist>
becomes
<menulist id="payment_type">
<menupopup id="payment_type_menupopup">
<menuitem id="payment_type_menuitem1" label="&staff.patron.bills_overlay.cash.label;" value="cash_payment"/>
<menuitem id="payment_type_menuitem2" label="&staff.patron.bills_overlay.check.label;" value="check_payment"/>
<menuitem id="payment_type_menuitem3" label="&staff.patron.bills_overlay.credit_card.label;" value="credit_card_payment"/>
<menuitem id="payment_type_menuitem4" label="Patron Credit" value="credit_payment" />
<menuitem id="payment_type_menuitem5" label="&staff.patron.bills_overlay.word.label;" value="work_payment"/>
<menuitem id="payment_type_menuitem6" label="&staff.patron.bills_overlay.forgive.label;" value="forgive_payment"/>
<menuitem id="payment_type_menuitem7" label="&staff.patron.bills_overlay.goods.label;" value="goods_payment"/>
</menupopup>
</menulist>