How can I view the sum of all documents and data records in a specific File Cabinet?
You can view the total amount via the following workaround:

1) Create a new scheduled Autoindex

2) Within the Match Data Tab, please select the file cabinet database from the file cabinet selected in Step 1

3) Tab "Assign Data" can be left blank
4) Within "Write Back" you can use the default configuration
5) Save the Autoindex Configuration
6) Go to the Autoindex Menu within the Web Configuration
7) Start the created Autoindex by clicking on "start now"
8) If the job is done, you can click on the last run of the Autoindex and you will see the amount of Documents and Datarecords within the file cabinet