QWidget includes a QWebView: horizontal line visible on middle of application screen if split view closed after orientation switch

Preconditions:

QWidget includes a QWebView with url input box and some HTML content. View is on portrait orientation.

•tested with pvkb-addressbook test application: select 'Web' button (but not any link on the page!) and tap the url input box on top of the screen --> split view is open on portrait mode

Test steps:
1. Switch to landscape orientation.
--> split view is open on landcape.
2. Switch again to portrait orientation.
--> split view is open on portrait orientation.
3. Close split view

Expected result:
Application screen is correctly displayed.

Actual result:
Application screen is divided into two parts: black horizontal line is visible in the middle of the screen.