A quick method to search for values in custom fields is by the screen "Search in Custom Fields". This screen allows to search in specific custom fields , but also allows to search for a value in all custom fields. Please contact support in case the screen "Search in Custom Fields" is not in your menu.
Another method to search in custom fields of a specific entity is to add the custom field to a dataspy. When editing a dataspy that shall include custom fields, it is advantageous to specify a class as it will limit the list of custom fierds considerably. The custom field selection can be found at the bottom of the list on the Layout tab. Please double click the "Click here" to make it visible.
Please note that only custom fields that have been configured to appear in the dataspy listing are shown.
Please contact support to add further custom fields or consult the document Tips & Tricks no. 19 – Searching in Custom Fields for more information.