On windows, all content is lost when saving files

[ChungZH]

Briefly describe this bug:

On windows, all content is lost when saving files.

How can I trigger this bug:

1. Open a file
2. Edit it
3. Save it

What is expected to happen

Screenshots

If appropriate, please attach some screenshots.

System Information

• OS Type(Windows, Linux or macOS): ALL
• Built from the source or download from the release: Both
• Version string in the AboutWindow: 0.0.3-alpha1

Affected Notepanda installation source

• [ ] ArchLinux AUR
• [x] Compile manually
• [x] Github Release

Other Info

You may want to write anything if you think it helps us to fix the bug.