QGraphicsWebView: Background application visible if QComboBox item list opened while Split view

Preconditions:
QGraphicsWebView includes url input field (QLineEdit) and some HTML content. View is on portrait orientation.

• tested with pvkb-addressbook test application: select 'GWeb' button and type 'http://www.google.fi' to url input field

Test steps:
1. Select 'Tarkennettu haku' ('Advanced search') from www.google.fi.
2. Tap some text input field
--> split view is open on portrait mode.
3. Tap small arrow icon on some of the QComboBoxes on 'Tarkennettu haku' page. E.g.

Expected result:
Item list is opened and no background application is visible.

Actual result:
Item list is opened (even if its position is sometimes odd, e.g. on top/left corner of the screen) and background application is visible on virtual keyboard area.
When item is selected from the list, the split view is closed.