Just go to file -> Preferences ->untick automatic interface scaling

Then choose a different percentage, click OK and restart Processing.

Well that was easy. Thank you so much!

Is there a way to make the menu appear a bit bigger? The editor got scaled up but the menu did not follow.

I don't think there is but you can check the processing code and might be able to change the size of the menu there.

Just go to file -> Preferences ->untick automatic interface scaling

Then choose a different percentage, click OK and restart Processing.

I actually thought this changes the size of the menu but it didn't.

I opened a discussion on Processing Discourse.
Maybe somebody else can help there.
https://discourse.processing.org/t/change-size-of-menu-bar/22086

The bundled version of java Java is 1.8.0_202 from ~/processing-3.5.4/java/release. Which does not appear to support automatic hdpi scaling. With the OpenJdk you can install version 9 which appears to solve the problem for other programs.
see

But since this project use Oracle's version, I'll have to test the program with a more recent one by changing the default configuration.

Can you try with the 4.0 alpha 2 release and let us know if it's working better?

Where the 4.0 alpha 2 can be found?

Edit: ops, it is a separate repo 🤪

In 4.0 alpha 3, the menubar is still small, but the menu items are bigger now:

That looks like a problem with the Window Manager you're using. Perhaps try another and see if it's still a problem?

Should be resolved in the 4.0 releases: https://github.com/processing/processing4/releases

The scaling seems to work fine with beta 1 on GNOME/Wayland now:

Thanks for the verification.

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