Follow the standard help page on Make a New Menu Item. After that is done you should now change the code in the sMIoOnClick attribute. This code will configure the listbox display.
The sMIoOnClick code uses standard JSON. Below is an explanation of the different elements with the JSON code. You can also download a text file that has the same code for your reference.
Result of Custom Listbox Menu Item Configuration
You can see by the screenshot that this type of listbox can be very useful. You can place it where ever it is needed using the Menu System, as well as filter who can use/view it.
 Sample JSON Configuration for NVR Listbox | [Actual JSON Code used for the sMIoOnClick button] | 1 kB |