When I add money from my Rabobank account to my bunq account, I use the "Add money" ("Geld toevoegen") feature. I the select iDeal (I like the new list by the way). Then it takes me to a list of prefilled amounts with my previous transferred amount selected. This can be handy, however, I never transfer the same amount. So I hit the pencil icon to edit the amount. This allows me to edit the amount but I want to enter a new amount so I have to hit back (usually) 5 times before being able to add a new amount. My suggestions: Hitting the pencil should wipe the amount or there should be a cross (x) to wipe the amount, or perhaps even one screen earlier there should be an option to enter a custom amount directly.
It sounds like a small thing but every month I have to do this multiple times and it gets annoying.