This patch adds a simple ui to kanban showing when you are trying to move an issue to a status that is not allowed (it disables the column and the issue) according to available workflows.

Also when you change the order of an issues (move it above or below another in the kanban) it doesn't drop the icon (sortable-ui) to move the issue afterwards.

These are patches for 1.6.1 light (both) and pro versions (separated).

Please consider implementing this feature.