As discussed on IRC: IMHO the "Port Log" icon should always be visible, even if the user doesn't have Port Control rights and/or Port Control isn't enabled. Currently the icon is hidden and only shows on mouse-over when Port Control is enabled.
I didn't find any open tickets about this, only a reference to commit [06f62f9] in https://sourceforge.net/p/netdisco/netdisco2/4/#4b87. Not sure if that helps with finding the relevant code and/or possible fixes.
Thanks for the report. Fixed in commit [28c6e5d] and will be in the next release.