In the C&C Napoleonics v4.0.6 module I have defined two LoS threads. The buttons for each are contained in a Toolbar Menu.
The normal appearance of the toolbar is:
with the toolbar beneath the LoS button showing as:
In an online game, just as my opponent selected one of the LoS menu items (Private, I think); one of the buttons appeared also in the main toolbar as well as being in the toolbar menu (see below). This condition persisted, even after the LoS was turned off and then to the end of the game.
Module: C&C Napoleonics v4.0.6 (at time of posting this is the current release).
Main Map / LoS threads x 2 and Los Toolbar menu.
I am not sure if this was a one-off glitch or a more reproducible problem. I don’t recall seeing it before in the several online games that I have played with the module since introducing the LoS toolbar menu. However, I have only recently started using the module with Vassal v3.6.