Though the roles are removed, you need to further check all the existing permissions assigned to this particular role. Try removing one by one and you will reach to a point where you see those dashlets are gone,
I faced this problem other way around. I had to add permissions one by one to reach to a point where I could see the agent's own stats dashlet to be shown in the dashboard.
------------------------------
Sajid Abbas
Al-Futtaim Technologies
------------------------------