Only 20 items shown in cascading combobox

Hello. We are using cascading comboboxes to load 1st and 2nd level admin units (regions/states) to pick the location where the survey is taken. Now we see that in the Interviewer Android APP, not more then 20 items are shown in the cascading comboboxes. Using the web app itself, this issue is not there and one sees ALL entries. In the Android APP one can start typing in the combobox and have the non-visible entries appear and one can select, but this is rather clumsy ! I may have seen something in the manual that says there is a restriction for displaying more than 50 entries in a combobox, but it shows only 20 in our case !! Anyone who can shed some light on this, please do so !! Cheers, Joost.