qt is always rendered on top of blender,
so when you try to close blender, sometimes the save scene dialogue is hidden behind a qt widget.
this leads to confusion, since blender is now frozen, but the qt widgets are not.
to fix this, we reimplement the dialogue in qt, and render it on top of everything.
we freeze input to force user to deal with the popup.
hannesdelbeke
commented
1 year ago 
qt is always rendered on top of blender, so when you try to close blender, sometimes the save scene dialogue is hidden behind a qt widget. this leads to confusion, since blender is now frozen, but the qt widgets are not.
to fix this, we reimplement the dialogue in qt, and render it on top of everything. we freeze input to force user to deal with the popup.
original blender style, but hidden behind qt
new qt dialogue , always in front