Does saving a model clear the Undo stack in Creo Parametric?

Hi everyone,

We are currently developing a Creo TOOLKIT-based connector that synchronizes Creo models with an external system.

As part of the synchronization workflow, the connector needs to detect changes made to the model (such as newly added parameters or geometry modifications). Before these changes can be synchronized, the model must first be saved so that the latest state is available. To avoid requiring users to manually save after every change, the connector automatically saves the model when necessary.

However, we've observed that once the model is saved, the Undo history appears to be cleared. As a result, the user can no longer perform undo operations on the model that were enabled before the save.

In some other CAD applications (e.g., Autodesk Inventor), saving the model does not clear the Undo history, allowing users to continue using Undo even after an autosave.

I'd like to understand whether this behaviour is expected in Creo.

• Is it by design that File → Save (or ProMdlSave()) clears the Undo stack?
• Is there any recommended TOOLKIT workflow to save the model while preserving the Undo history?
• How do other Creo TOOLKIT developers handle this scenario when implementing autosave for update/publish workflows?

Any clarification or recommended approach would be greatly appreciated.

Thanks!