Undo causes crash

**Describe the bug** Undo button causes Crash **To Reproduce** Steps to reproduce the behavior: 1. accidentally delete something 2. press undo 3. note crash **Expected behavior** Doesn't Crash **Desktop (please complete the following information):** - OS: Win10 - Architecture: x86 - Version: [v2.11.4](https://github.com/Lolle2000la/Image-Sort/tree/v2.11.4)