Desktop file actions

Hi,
I have a problem with the desktop file, the issue is explained here on github: https://github.com/flathub/io.typora.Typora/issues/2

This app is ultimately a text editor, I’ve implemented a new-window desktop action to open a new empty window.
But flatpak still opens a new instance editing the same file already opened in the last instance.

Is there anything else I should try to fix this issue?
Thanks