Save as wipes undo history

[lmoellendorf]

Describe the problem

Using "Save as..." to save a duplicate the original sketch, closes the original sketch and opens the newly saved one.

This wipes the undo history of the original sketch.

The use case is:

I edit an existing sketch and save the changes. Then I realize I would like to have the original sketch and also keep the latest changes. Natural thing to do is:

1. Save a copy of the current state of the sketch, then
2. undo the changes in the original one and
3. save the original one

To reproduce

1. Open and edit a saved sketch
2. Use "Save as..." to duplicate the sketch
3. Try to undo the edits to the original sketch

Expected behavior

The orginal sketch should stay open and its undo history preserved.

Arduino IDE version

2.2.2-nightly-20240104

Operating system

Linux

Operating system version

6.1.46-gentoo-x86_64

Additional context

No response

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details