Description:
I use track changes and when I show deletions in margin and then call undo the program crashes.

Steps to Reproduce:
1. Opening a writer new document.
2. Input some text. For example “Sometext”.
3. Go to the tab "Review".
4. Enable “Record”.
5. Delete some letters of the entered text. For example delete “ext”.
6. Disable “Record”.
7. Input some letters. For example “est”.
8. Enable “Show -> Deletions In Margin”.
9. Click the arrow Undo.
10. Writer crashes.

Actual Results:
Crash

Expected Results:
-
Reproducible: Always
User Profile Reset: No

Additional Info:
Also the bug can be reproduced on version 7.3.6.2 and earlier.