Variables are normally referenced by assigning the variable name to the task field within the Behavior Designer inspector panel. Local variables can also be accessed . . .
a key to fit all behavior tree in the screen, i use shift+space to maximize Behavior design window but it moves to side or else losing the focus
like in unity "A" key in the animator window fits all the animations
its not much, but then I need to use mouse middle button repeatedly which can cause little discomfort on shoulder
There isn't a feature like that built in but I can take a look at adding support for it. I noticed that you left a review for Behavior Designer about the documentation - is there something in particular that you are having trouble finding?