With filmstrip on top:
- after Ctrl+Shift+P the preview disappears
- thumbnails are shown topdown in columns
1 5 9
2 6 .
3 7 .
4 8 .
instead of rows
1 2 3 4 5 6 7
8 9 . . .
- way back works OK
With filmstrip on bottom:
- after Ctrl+Shift+P the preview disappears
- all thumbnails disappear
- only a mouse cursor for horizontal width adjustment of folder tree remains

- way back works OK