When trying to open a new tab from the terminal using, for instance on mac osx, /Application/Waterfox \ Classic.app/Contents/MacOS/waterfox --new-tab about:blank Waterfox will just print the error "A copy of Waterfox is already open. Only one copy of Waterfox can be open at a time."
If there is no Waterfox instance currently running it will work but only once as trying to open another tab at that point will print the previous error message again.
OS: Mac OSX 10.7
Waterfox classic version: 2022.4 (64-Bit)
When trying to open a new tab from the terminal using, for instance on mac osx, /Application/Waterfox \ Classic.app/Contents/MacOS/waterfox --new-tab about:blank Waterfox will just print the error "A copy of Waterfox is already open. Only one copy of Waterfox can be open at a time." If there is no Waterfox instance currently running it will work but only once as trying to open another tab at that point will print the previous error message again.
OS: Mac OSX 10.7 Waterfox classic version: 2022.4 (64-Bit)