'Show method parameter names' option interferes with split/cloned editor behavior

[harawata]

Eclipse IDE for Enterprise Java and Web Developers (includes incubating components)

Version: 2024-12 (4.34.0)
Build id: 20241128-0757

I could reproduce this on...

• MacBook Pro (M3 Max) macOS 15.2
• Mac mini (i7) macOS 15.2

Steps to reproduce

1. Create a new 'simple' maven project. Specify "test" for both group and artifact ids.
2. In the Preference, enable 'Show method parameter names' (Java > Editor > Code Minings).
3. Create a new class TypeParameterResolver under the package test.
4. Delete the default file content. Then copy & paste the content of this file and change the package declaration to test, then save the file. 

   Note that the problem is not specific to this particular class. It's just the easiest one for me to explain.
5. From the menu bar, choose Window > Editor > Toggle Split Editor (Horizontal).
6. Without clicking the editor itself (i.e. using mouse wheel or trackpad), scroll the lower editor to the bottom of the file.
7. In the upper editor, click to place the caret right after the semicolon of package test;.
8. Using keyboard, type a character "a".

Expected behavior

The lower editor keeps showing the bottom part of the file.

Actual behavior

The lower editor automatically scrolls to the package declaration line.

Additional info

• The issue reproduces with vertically split editor and cloned editor as well.
• After the step 8, interestingly, Undo does not work. Pressing Cmd+Z does nothing and the menu item is greyed out. I'm not sure if it's related, though.
• Unchecking the sub-options ('Filter parameter names that are implied by parameter' and 'Default filter for some specified methods and method parameter names (e.g. compare())') does not seem to affect the test result.
• With this particular steps on a newly created workspace, editing the lower editor does not scroll the upper editor, however, in my daily development, editing the lower editor also scrolls the upper editor. I am not sure what the difference is at the moment. It might involve some other factors.
• I cannot confirm whether this is a macOS specific issue or not, but there are several people asking about the same issue on Stack Overflow and none of them mention Windows while some mention macOS.