If I'm not mistaken, it's not wrong grammatically to end a sentence with a preposition, but it goes against established convention. Best I can tell, that convention is on its way out.
I blame that on kids with their damned cell phones and rap music.
Oh... well, technically, (Ozzie), none of the menu items are actual sentences. They're fragments, or bullet points... so the preposition rule does not apply.
If the item was "Show me topics I have posted in[.]"... then we'd have a valid case for a grammer rule application. If it doesn't end in a period, it's not a sentence (sort of).
- Wil
Yes, this is exactly what I was thinking. "Topics I've posted in" is not a sentence as there is no command in the fragment. "Topics" is the noun, "I've posted in" is describing the noun.
Your resident eight-grader