If widget A starts at y=0 and widget B starts at y=19, when the mouse
moves from y=15 to y=18.6667, the code was doing childAt(p) with a
rounded QPoint y=19 and finding B, but then the relative coord for B
was set to -0.33333 so B wasn't under the mouse and didn't get an enter
event (and since it's now the "last receiver", it doesn't get one later
either when y is bigger).
Add QWidget::childAt(QPointF) to fix this.
Fixes: QTBUG-128391
Change-Id: I76d4b711a8297648780bdd079eb67405ab12be14
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 40bde8a572bd8ed039d3f5a5ab99b281de7410bd)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
cd528d81f7