Image cropper allows out-of-bounds selection

When cropping an image, it is possible to make the selection area bigger than is allowed by the ratio of its variant.

For example, the default thumbnail variant is 60 x 60 . This means the cropping selection should always be a rectangle shape. However, by trying to select the whole image the selection area can go out-of-bounds.

This is, however, only a visual issue, i.e. the crop action is never affected by the out-of-bounds dimensions.