With the new footnote/comment system, if you have a footnote and try to insert a comment in the same spot, the comment will overwrite and remove the footnote. Same in reverse. It’s particularly a problem if your practice is to insert at the end of paragraphs.
What are you trying to accomplish here? You basically want to annotate the footnote? Since annotations are just free-form notes to yourself that are commonly stripped out of the compile, why not just put it right after the footnote that needs commentation or somewhere else nearby? I do see a slight overlap on the “bubble” that is drawn around them though, when they are directly adjacent; that could use fixing.
No, to give an example, I’ll often have a footnote at the end of a paragraph that applies to the preceding paragraph, which is a fairly standard editorial practice. If I place the cursor after the last period and hit the insert footnote button, it’ll highlight the last word and apply the footnote. Sometimes we want to add a comment also for follow-up, collaboration notes, etc. Placing the cursor after the period again and hit comment will again highlight that same last word and overwrite the footnote silently. It would be good if it there was at least a warning, or, better yet, the two could coexist.
This is not a bug: they are either/or, so both cannot be applied to the same piece of text. A warning would be overkill, because you can just undo the action as soon as you see what has happened, and really it’s just a learning curve (do it once, realise what happens). However, you could just use an inline annotation instead, which gets deleted on compile.