The 'pull-to-refresh-inbox' is very 'heavy'. The amount of swipe required to pull down the refresh is unfriendly. Some times it gives me the feeling I am not going to reach the full pull required for it to work.

I would suggest increasing the height of this refresh-bar for a more lightweight feel to the refresh (so for the same amount of swipe it would show a higher 'pull-to-refresh-inbox-block'. Possibly the amount of swipe required to initiate the refresh could be decreased at the same time.

It would also be nice to see in the bar when the refresh is triggered, i.e. also show the refresh spinner once the refresh is triggered.