Form elements not rendering on scrollable popup android

Form elements not rendering on scrollable popup android

Hi,
on m Page ( https://ovbportal.hu/ovbphp/public/temp/testNaptar.html#&ui-state=dialog) I have a popup which is bigger then normal phone screen, and is therefore scrollable. However on Android some form elements are not rendering correctly (mostly those, which are not on the screen when the popup is shown - select but also the buttons at the end are not showing). See for example: the first and last elements of the first select are not showing.
Any help would be appreciated
Thanks
Greg