Unable to undo (cntrl-z or undo button) after deleting

[bryantwong]

In a .sagews document, I'm able to replicate an issue where undoing doesn't work.

If I start in some cell above the markup that gives a problem (see attached image), then press Shift + Down-Arrow some number of times until I've highlighted the markup and some cells above and below that ,

and press delete,

I am unable to undo the deletion.

Neither control/command-z or the undo button will return the document back to its previous state.

[haraldschilly]

might be a silly question, so late, but do you still have that worksheet? send us a link at [email protected] with its URL.

[williamstein]

I followed the directions above (with the screenshots) and was very easily able to replicate exactly this error. I just started with any very simple worksheet. It's a serious problem that we'll definitely want to fix.

[bryantwong]

I don't think this problem is worksheet-specific (I accidentally experienced this problem many times in my class), but I believe the specific worksheet is located here:

https://cloud.sagemath.com/projects/741fb650-cb46-469a-be47-befe9db6ed8a/files/homework1/hw1.sagews

I'm not sure if you will be able to access it but I can add you as collaborators as necessary.