setting QTableView stylesheet (even empty) blocks almost all QPalette effects

I would like to customize QTableView grid line color by setting stylesheet. Problem is that if I set any stylesheet (even empty) for QTableView then it stops to read almost all settings done by setPalette( QPalette ). I expect that all settings not affected by stylesheet can be changed in other way (in this case by setPalette).

I made simple example, where I test every QPalette::ColorRole, but the only visible change is the bottom-righ square batween horizontal/vertical scrollbars (if they are visible).