It sounds like maybe you have one single Player hand map window with all your individual boards added to that. You’ll actually want a new Player Hand window, with its own board, for each player. Sorry if something I said earlier mistakenly caused you to think only one player hand window itself was needed (or if I’m mistaken now in that assumption). So each player needs a Player Hand window, and a single board added for that window, and then that player needs to be assigned to that window via its ‘belongs to side’ property.
The issue with the deck is probably due to your not being in control of that player hand window. The side you sign in as has to be listed in that window’s ‘belongs to side’ property. I’d prefer seeing a generic map window used for a communal board, but if you make a Player Hand window that belongs to all players, then ensure that every possible player side is entered into its properties.
Lots of flexibility with toolbar buttons… you can hide buttons on the toolbar (but still have them open/close with a hotkey), and you can group several into a single ‘menu’ button, and you can activate a bunch with just one click (multi-action button)… so lots of options for both main and individual toolbars, which is great.
Check pg 13-16 - Using Properties - in the Designer’s. The basic piece wiki has a good list, and individual wiki pages (via the help button in the editor), will give you properties associated with whatever you’re working on.
vassalengine.org/wiki/BasicPiece
vassalengine.org/wiki/Properties