QGraphicsView with vertical scrolbar flickers somewhat when splitview opens

When opening an application that has:

• maximized window state
• contains proxy widget
• is showing vertical scrollbar,

application flickers rather badly when opening a splitview keyboard.

This caused by several operations happening almost simultaneously.
1. Windowstate is changed to fullscreen
2. graphicsview is translated upwards
3. focusitem is ensured to be visible in the center of the available screen

All of these should happen inside updatesEnabled(false) - updatesEnabled(true) guards.