Basically, making mistake in error typing is something that happened regularly but in as much as you exhibit the habit of reading your context after posting will certainly show you your error, sometimes I find errors in my post after 2-3 days when just scaling on my posts history, and the edit bottom had been helpful.
Ah, I wasn't aware of that five minute time limit--thanks for pointing that out.
The exact time it takes before it shows edit is 10 minutes not 5 minutes, I think ocTradism should correct his mistake.
There won't be any dotted line if the edit was within 10 minutes after posting.
I think it's 10 minutes.
The edit time will be displayed only if you edit your post after 10 minutes.
Majority says it all.