If you cursor is on an empty line inside the fold then the left move (l
) will not work, thus it won't open the fold.
The same happens if your cursor is at the last column in the line. But in this case an h
will make the fold open.
You can check if the a movement command fails by paying attention to the error beep, the same it issues when you hit Esc
when you are in normal mode. If you are unable to hear it, you could try using the 'visualbell'
option.