View model is changed by attempting to delete dependent source model and previewing delete

1) Import attached project set
2) Open ProductViews model in editor to show package diagram
3) Select ProductsDB2_VDB model and click DELETE
4) In Delete refactor wizard click Preview> button
5) Cancel all and the ProductViews editor tab will be dirty (requires saving) and the package diagram is cleared out.

Wondering what EMF data is getting set/changed to cause the dirty editor?