In CET 15.5, support for undo operations on CustomerOwnMaterial actions has been added.

The following function has been removed as it was previously migrated. The existing function, public bool buildMaterials(TreeViewItem item0, TreeViewItem item, bool open), should be utilized.

Removed: extend public bool buildMaterials(TreeViewItem item0, TreeViewItem item) {}
Existing: extend public bool buildMaterials(TreeViewItem item0, TreeViewItem item, bool open) {}