Hello Tom,
Providing some Model Manager java customization, you can enable and disable BOM Editor from ribbon as shown in here attached "BOMManagerRibbonTools.PNG".

In this example, I put a couple of buttons in the new "ACME Tab" in order to enable or disable the BOM Editor module. You may set the buttons in any other tab as you like.
The work is done by a couple of java classes and a XML configuration. You will find all this material in the here attached "custom.zip".
You may test your Model and Drawing Manager client without any development environment using the following:
- copy the classes files in the same path in your Model and Drawing Manager client
- edit your custom.xml adding the Ribbon section, just after the Options section
- and start your client
To populate the solution, then do the following:
- insert the src files in your development environment
- edit your custom.xml
- compile your project
- and finally build (mmbuild) your ModelManagerSetup.exe so that clients may update
This has been designed and tested against Model Manager 20.0 F000; I guess it should work on some previous versions. Tell me how does it work with yours.
Hope this will help.