Some functionality in Flex does not respond to adding activity as smart as previous mobile did.
When searching the search feature use to narrow down the list based on searched letters, now you need to click search (an extra step).
Selection customer = was default G, now you need to select the division - get everyone
Then you are asked again when selected which division after you have selected the customer
Then you click to select contact (previous version use to select the most selected - most frequent.