Mouse wheel scrolling broken when running on secondary desktop

Immediately noticed the breakage when updating Qt Creator from 4.7.1 to 4.8.0.
Due to the symptoms it's most likely a Qt issue rather than Qt Creator, so filing here first.

My code editor stopped responding to mouse wheel scrolling after the update. Same for the side panels.

I have a dual-monitor setup, the main monitor being the laptop's, and a secondary monitor on the right side, with "extend my desktop" setting on Windows. I have Qt Creator running maximized on the secondary monitor.

If I move the Qt Creator window back to the primary monitor, scrolling is back to normal.

Moving back the window to the secondary monitor, scrolling breaks again (even if I explicitly click on the editor pane to give it focus).

Then I got a clue as to what's happening: scrolling starts working again if I move the mouse towards the right side of the screen. But as I move it towards the left, at some point with the cursor getting near the center of the screen it'll start scrolling the side bars, then once I pass the center it just stops scrolling altogether (and my cursor is still within the code editor).

What seems to happen is that the wheel events coordinates are miscalculated, mapping the secondary monitor's local coordinates to the whole virtual desktop, or possibly not applying its offset correctly when mapping coordinates, so Qt picks the wrong widget/component to send the wheel events to. I can't tell if it's a QPA bug or somewhere down the translation chain.