Eclipse Saving file clears undo history

I have a habit of hitting on Ctrl+s to save my file every now and then. What I find with my current Eclipse setting is that once the file is saved I lose all UNDO history in the buffer -- Ctrl+y no longer does anything.

Is there a way to change this setting in eclipse? I want undo history to be kept until the file is closed.

How to check history in Eclipse file?

In the Eclipse Navigator view (or any Eclipse view that supports Team operations), right-click the file or folder and click Team > Show History.

We have just found a similar situation where the undo history wasn't available anymore after saving. The reason seemes to be that the editor has been "crashed" and doesn't work anymore as expected. The solution is to simply close the editor tab and reopen the file in a new editor.