Changing arrowhead from normal to none does not work

[cwtsteven]

Hello! In my application, I need to change arrowtype dynamically from normal to none and vice versa. However after changing it, the arrowhead still exists.

I am running Firefox 53.0.3 (64-bit) on Mac Sierrra 10.12.4
Steps to reproduce:

digraph G {A -> B [arrowhead=normal]} 

then

digraph G {A -> B [arrowhead=none]} 

Second (related) issue:
Changing arrowtype to dot does not erase the old arrow, and the dot seems to be permanently added to the edge. This case is particular for dot.
Steps to reproduce:

digraph G {A -> B [arrowhead=normal]} 

then

digraph G {A -> B [arrowhead=dot]} 

then

digraph G {A -> B [arrowhead=crow]}