On --help, I see:
-n - Ignore option "ui_one_instance", open new app window
I want the opposite. I want one single window. How do I get that behavior?
Tried -id=name - Set single-instance id, for groups of instances (Unix, default: cudatext.0)
But it doesn't do much different?
Single window mode
From hereHow to open files in a new tab instead of a new window
Option "ui_one_instance" controls it, so change it to 'true' (without quotes, in "user.json"). This option is here for several years already, but people are asking this question again and again (forum, GitHub, Linux forums). Seems the term "instance" is not known very good, people cannot find this option easily.
(Another way to change the option is in the Options Editor - in menu "Plugins > Options Editor...")