Sometimes it went wrong when I wanted to delete pictures through the panel.
I go to the gallery.
I select 1 picture.
I see 'delete 1 selected'-text on hover over button (OK).
Confirm it by clicking delete button.
The file will deleted.
Then I select the next picture to delete.
I see 'delete 2 selected'-text on hover over button (not OK).
Confirm it by clicking delete button.
Then whole folder will be deleted!
When I do a refresh of the page (F5), after I delete the first picture, it will be working OK.
I tested it on Windows 10 with Chrome 49, Edge 25 and Firefox 44, and on Android 5.1 with Chrome 49. But it is the same everywhere.