Sadly JFoenix is not developed anymore. Using JFoenix with JPMS was very clumsy.

• Replaced call to SwingFxUtils with some native code
• Removed JFoenix Colorpicker with vanilla
• Replaced JFoenix Chipview with GemsFX TagView

Turn autocompletion on and restart JabRef to test this.

Mandatory checks

• Change in CHANGELOG.md described in a way that is understandable for the average user (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.