Combobox is pushed off-screen by virtual keyboard after selected an item and lost focus [iOS 8.1]

Reproducing steps:

1. Open the sample page in iOS Safari
2. Click the combobox button to open the dropdown
3. Select one of the item
4. Click outside the combobox
-> The text in the input node is selected in full. Virtual keyboard shows up. Combobox is pushed up and becomes off-screen.

Reproducing code:

<combobox>
    <comboitem label="Comboitem 1"/>
    <comboitem label="Comboitem 2"/>
    <comboitem label="Comboitem 3"/>
</combobox>