Comment gadget

Hmmm, that probably wouldn't work very well. If I understand correctly "wikipedia:wikt:" only directs to the English Wiktionary from English-language projects that are not Wikipedia itself. I don't know of any set of interwiki prefixes that would reliably lead to the correct page.

Re the indentation: Usage of "*" complicates this somewhat. The preview would need to be done in isolation, but some indentation doesn't look the same if it's preceded by other indented content. Example:

• Lorem
  • Ipsum

shows one dot before the second word, whereas

• • Ipsum

alone shows two. I still haven't thought of a solution to this issue.

It is tempting to make a perfect solution, but this might be overkill. Often I need this tool when I only have my phone at hand. Later, when I'm back at my laptop, I can correct any minor errors by full editing.

Actually, it seems one can use directly the "wiktionary" prefix, which links to the English Wiktionary (check here for mediawiki's default values, and here for a non-English WMF wiki with a customized interwiki map).

Regarding the indentation, how about indenting the text box as much as the last comment, in order to discourage usage of constructs such as **, :*, etc? The indentation in the preview seems to be working well already; I'll let you know if I come across any edge cases.

Finally, appending a warning under the text box --say, right after the cancel button-- when a signature is added (3 to 5 tildes) would be a nice touch, like LQT already does.