
It appears that it is no longer possible to create a full-width cover image via the editing interface. Maybe I am just missing the way to do it, but if it is really no longer possible, then this feature should be removed from the demo content and its CSS rules should be removed.
In my opinion it should definitely be possible. This is pretty common design pattern and it would be inline with image block.
See also #2650.
@nylen You can set 'wide-images' => true, in add_theme_support( 'gutenberg' ) and after that you can set full width cover image. But alignwide or alignfull are still missing in the markup. Those should be added.
I'm not aware of the context behind making this available on a per-theme basis, but it sounds sensible.
So I think the only thing to do here is to remove the full-width cover image from the demo content, since this can't be recreated on a standard install.
I'm not aware of the context behind making this available on a per-theme basis, but it sounds sensible.
It's because Gutenberg can't know is there room for full width or wide, and what that even means on theme by theme. There can be sidebars in the left or right etc.
Closing as duplicate of #2595.
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https://weblines.com.au/gutenberg-blocks-wide-alignment-full-width/