There is on very rare occasions a case where a panic occurred at line 152 of layers.rs when a Viewport exit.
( At this time, self.0.len() == 0 )

( On screens with different pixels_per_point. )

thread 'main' panicked at C:\prog\egui\crates\egui\src\layers.rs:152:15:
index out of bounds: the len is 0 but the index is 0