Bpmn2 scheme questions

Hi.

I have some questions about bpmn2 that don't leave me alone :)

1. Why after saving changes in workbench always changes all ids of xml elements? Is it possible to turn off this behavior? It is very difficult compare changes in git, honestly, it is impossible.
2. In which xsd schemes I can find describe of elements like this : "drools:selectable", "drools:dg", "drools:fontsize" and others? There elements you can find in simple bpmn2-process schemes.

I honestly looked for answers to these questions in Google, in GitHub but never found. Help please

Regards,
Alexander Ivanov