Whitespace rebalancing of the fragment creates the problem demonstrated by: nested-blocks-with-*.html Unrendered whitespace at the end of the fragment are uncollapsed by whitespace rebalancing. Functions that create fragments should be responsible for using nbsps where appropriate.
Only two tests related to it in /editing/: https://github.com/WebKit/WebKit/blob/422c18c5dba37299622f8634c99d776ec1b017f9/LayoutTests/editing/pasteboard/nested-blocks-with-text-area.html#L4 https://github.com/WebKit/WebKit/blob/422c18c5dba37299622f8634c99d776ec1b017f9/LayoutTests/editing/pasteboard/nested-blocks-with-text-field.html#L4 These tests does not seems to be skipped and are matching their expectation and recently we fixed nbsp related bug as well. Do we need to do more or someone knows background about this bug and can explain more? Thanks!