Shotcut freezes when using system open/save dialog with using Clipboard (Linux Mint)

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OS and Version (please complete the following information):

• Operating System: Linux Mint 22.1 Cinnamon, based on Ubuntu 24.04. Cinnamon version 6.4.8,
• Shotcut Version: 25.07.26, shotcut-linux-x86_64-250726.AppImage

Describe the bug
When try to open/save with system dialog, after trying cut/copy/paste filename, shotcut and dialog freeze.

Steps To Reproduce

1. Start Shotcut
2. Open file / Save file
3. Type something on filename
4. Select some chars of the filename and try cut/copy (both mouse and keyboard work), and shotcut freezes

Expected behavior
Nothing wrong should happened

Screenshots
There is no screenshot. Instead, I recorded a video to show how it looks.
Here is the video link: https://youtu.be/IArElxb9zcU

More info

• Sometime the freeze will end after a long time waiting.
• I think this issue exists very long time ago, even when Shotcut was using a old version of QT.
• Other applications like xed and pulsar don't have this issue so I don't think my system is broken.

Start by reproducing the freeze using Shotcut 25.07.26 on Linux Mint 22.1 with the system open/save dialog, following the listed clipboard steps. No source file or test is identified in the issue; done means cut, copy, and paste in the filename field no longer freeze Shotcut or the dialog.