i have write a custom code in following file to show a button on detail page. when i Quick Repair and Rebuild, the custom code removed automatically. why this is happining.
custom\modules\Contacts\metadata\detailviewdefs.php
The custom code for button is
array(
'customCode' => '<input name="print_selected_sec" title="Print Card" type="button" class="button" value="Print Card" id="print_selected_sec" />',
)