Standard 3 Title update error if missing line 1 #5864

Describe the bug

When a "Standard 3" is missing line 1 we have many update problem:

• if both line 1 and line 3 are missing, line 2 is mutable (unable to update).

• if only line 1 is missing, update to line 3 becomes line 2, and update to line 2 is lost.

If line 1 is present and line 3 is missing, update to both line 1 and line 2 works as expected.

Steps to reproduce the behavior:

1. Add a "Standard 3" title and empty the content of line 1
2. Save
3. Try to edit line 2 and line 3
4. Observe the error

Expected behavior

"Standard 3" should work as expected even if some line are missing.

System Details

• OpenShot Version: 3.3.0
• libopenshot Version: 0.4.0
• Platform: Linux-6.8.0-79-generic-x86_64-with-glibc2.40
• Processor:
• Machine: x86_64
• Python version: 3.12.11
• Qt5 version: 5.15.15
• PyQt5 version: 5.15.11
• Qt Detected Languages: ['en-US', 'en', 'en-Latn-US']
• LANG Environment Variable: en_US.UTF-8
• LOCALE Environment Variable:
• Daily Build: Skipped this step

Log Files

• openshot-qt.log (8 KB)
• libopenshot.log (22 KB)

Exception / Stacktrace
No stacktrace found in log files

Screenshots (Optional)
If applicable, add screenshots to help explain your problem. You can include screenshots by
copy/pasting them on GitHub or dragging-and-dropping into the GitHub page. All images are public,
so please don't post screenshots containing personal information.