v4: `removable:true` not working

[adumesny]

Subject of the issue

looks like I broke removeable:true options when I re-wrote drag&drop (works ok with class name which all demos use).

Your environment

• 4.2.3 win10 chrome

Steps to reproduce

spec/e2e/html/1570_drag_bottom_max_row.html

Expected behavior

remove when leaving the grid