Latest Comments block having issue with alignment

[nidhidhandhukiya]

Steps to reproduce the issue:-

1. Choose any theme between Twenty seventeen or Twenty Fifteen.
2. Choose Latest comment block.
3. Apply alignment.

You can able to see in both side editor and front there is no difference even if we choose alignment.
In editor some change is there when we apply alignment but not looks proper.

[tusharaddweb]

Test Environment:

WordPress Version: 6.8.1
Themes Tested: Twenty Seventeen, Twenty Fifteen
PHP Version:8.1

Test Scenario

Activate either Twenty Seventeen or Twenty Fifteen theme.
Add a Latest Comments Block to a page or post.
Apply different alignment settings (left, center, right) from the block settings.
Observe the behavior in both:

Block Editor (Backend)
Frontend (Live Site)

Expected Result

The alignment setting should apply correctly to the Latest Comments Block in both the editor and the front end.

Actual Result
In Block Editor (Backend)

❌ Alignment changes, but the appearance does not look proper.
❌ Misalignment or unexpected behavior in certain themes.

In Frontend (Live Site)

❌ Alignment does not change despite selecting different settings.
❌ The block remains in its default position regardless of the applied alignment.

Issue Summary

The alignment settings in the Latest Comments Block do not work as expected.
There is an inconsistency between how alignment is handled in the block editor and the frontend.

Attachments

​https://prnt.sc/SuhfpOIDBaA1
​https://prnt.sc/WZyi8FRyBHkG

Test Conclusion

Status: ❌ Issue Confirmed – No Fix Available Yet
Impact: Medium (Affects block editor usability and frontend display)
Recommendation:

Report this issue to WordPress Core developers.
Check for possible CSS overrides in the theme that might be affecting alignment.
Test on different themes to see if the issue is theme-specific.

[sabernhardt]

I did not find issues unique to Twenty Fifteen or Twenty Seventeen, so this might not involve changes to individual themes.

The Left and Right alignment options technically work by floating the block to one side or the other. However, the block does not limit its width by default. If the comments and post titles are all short, the block would align to the side. If any comment wraps to a second line, the block might look exactly like the no-alignment option. Twenty Nineteen, Twenty Twenty, and Twenty Twenty-One set a max-width for any element with alignleft or alignright classes; the older bundled themes do not.

The Center option has an ​issue on the Gutenberg repository.