On safe mode, some actions on parameter files are limited:

• Add a folder
• Delete a file or folder
• Move a file or folder
• Rename a file or folder
• Create or edit a file

This is due to org.ametys.plugins.core.ui.parameter.files.ParametersClientSideElement._checkNotSafeMode().
Note that all components (FileHelper and SourceResolver) for these actions are available in safe mode.