History Cleared When File Saved

Do not allow photoshop to clear history on an image until that image is closed, history is manually cleared by the user, or photoshop is closed. 

Example: I flatten a layered image, accidentally hit ctrl-save and history is cleared. I now cannot revert in history to regain my layered psd because I saved over it with the flattened psd. My fault. But WHY is the history wiped when the image is still open? What good is history if it is cleared before you close the image?