* use nullptr
* use member init
* set ExpandingFieldsGrow fieldGrowthPolicy for QFormLayout, which
makes it behaviors similar on macOS as other platforms
* select first row to make up/down keys works by default
Change-Id: I25d9869d2ca1c7274c2b750aada8270734787546
Reviewed-by: Liang Qi <liang.qi@qt.io>
(cherry picked from commit ed1fbc7a88008ddf118556a97f1ee34989151c75)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
c3efe23ad1