blockquote / quote isn't properly saved by the inplace and wysiwyg editor

This bug at least as old as XWiki 11.

The root cause of this issue is a limitation on the XWiki Syntax / Rendering side. There are actually two issues:

• You can quote only single paragraphs, see XRENDERING-259. The content you selected includes a heading, a definition list and multiple paragraphs. XWiki syntax doesn't support quoting definition lists, and it also doesn't support grouping multiple blocks under the same quote.
• Definition lists can't contain block content, see XRENDERING-233. The definition list you copied has multiple paragraphs.

On the CKEditor side, ideally the editor shouldn't allow you to:

• quote definition lists or multiple blocks at once, if this can't be saved
• include blocks in definition lists, if this can't be saved

We might be able to achieve this by properly configuring CKEditor's Advanced Content Filter (ACF). The outcome would be:

• the pasted content is filtered in order to fix the "invalid" content (from the point of view of the XWiki Syntax), which means the result after the paste will not look like what you see on https://git-scm.com/docs/git-clone (e.g. paragraphs will be moved outside the definition list)
• the blockquote button should be disabled when selecting content that can't be quoted in XWiki Syntax.

Obviously, the best is to improve the XWiki Rendering, but it's not easy.