Click on a cell does not always show picker/numpad?

[hao]

I am using IBAForms, and found a weird problem, I have a screen with several cells, they include normal keyboard, numpad and picker, if I tap on numpad or picker cell, the screen scrolls so the cell is centered, but the numpad/picker is not shown, but if I tap on a normal keyboard cell, the keyboard is shown and if I tap a keyboard cell first then tap on a numpad/picker cell, the numpad/picker is shown. Does anyone have the same problem?

Thanks!