Workflow reasign button hide
In current version (6.8) it is not possible to remove/hide reasign button. Each user can reasing task in every step of the process even though it is not allowed in process. Also users can see all roles, groups and users of current organisation which is unnacceptable and it is stopping workflows. Admin should have option to remove this button (show/hide), at least that.
The feature will be available with the next update.
Marcin Kratiuk commented
The partial solution is that it is possible to hide it using custom CSS.
It will hide the button. But it can not hide the menu entry on the context menu.
/* Hide "Reassign" button in workflow tasks */
button[title="Assign the selected task to another user"]
this should also be added for 6.9 as well.