Issue: Selective Quoting

Implemented in the next release. Please note that XenForo's Select-to-Quote function was only designed to work with regular posts, so it is not extendable across different content types. Implementing it at all for wiki comments required some hackish code.

You cannot select wiki comment text and expect to quote it in a regular post and conversely you cannot select post text and expect to quote it in a wiki comment. This will only be possible if XenForo rewrites the feature with multiple content-types in mind, and with a standardized method of implementing mixed content types. Since most other features were written this way, it's a little unclear why they opted to use a post-only method. If many users agree, I would suggest reporting this as a design flaw on XenForo's site.

How about selecting forum text to include into wiki? So when the text is selected show a 'wiki' option next to quote and reply.
As per this sponsored feature: https://www.vaultwiki.org/issues/2057/

Modifying the quote | reply popup could be a challenge. If it's even possible without completely replacing XenForo's function, then I agree it could be a useful way for at least getting the suggested text into a form (alternative to a button for full-post submissions).