SysML Flowport - embedded arrows do not display

[EA_Super_User]

I have created an IBD utilising 2 previously defined blocks and am in the process of embedding flowports in each block and creating information flows across the blocks via the flowport interfaces.  I have been setting the flowport direction (in, out, none) successfully.  Unfortunately the embedded arrows within all of the flowports have disappeared.  I checked the stereotype to ensure the port is a flowport and have checked the appearance properties of the flowport to no avail.

Update:  I reloaded my model back into version 7.1 and the flowport arrows are still not visible.  It appears I have inadvertantly disabled arrows from displaying but I can't determine where this option would reside.  Any help would be appreciated.