the close gaps function timestretches the events within a part so as to close the gaps between them using the algo chosen in file > preferences > editing > audio.
however, the options are limited to the standard mpex algorithms, rendering this feature quite limited.
seeing as audiowarp quantize is very poorly implemented, a solution to quantizing audio could be to slice the event up traditionally, quantize the sliced events, and then close the gaps – however this, as mentioned above, cannot be done using the elastique algos. (having said that, it would be neat if warp-quantizing worked correctly/predictably in the first place.