See, the thing is. A condition has a logic part (if true it runs its actions) and a picking part (it makes a list of selected objects).
If you want to set a Boolean based on the logic (true/false) you best use an 'else'. Else means 'if the previous condition did not run (hence it is false), run this condition.
If you want to set a Boolean to a list of picked objects (true), and set the opposite the unpicked objects (false), then the the second condition will be the first inverse. But, that second condition cant be a sub of the first because those objects are not picked by the first one.
Now, those two 'rules' combined. Often it means (for the logic based else) that the top conditions are the picking conditions. Then a sub with that logic condition, then attached to that sub the logic else. Or in general:
Pick object A
Pick object B
______Logic condition
_____________________actions
______Else
_____________________actions
Example
You want set a boolean if a object is onscreen, if none of that object is onscreen you want to set the boolean to false.
(object) Is onscreen
_____________________set boolean true
else
_____________________set boolan false
Or. You want to set a boolean of all instances of an object to true when they are on screen, and to those that are offscreen you want to set the boolean to false.
(object) Is onscreen
_____________________(object) set boolean true
(object) Is (NOT) onscreen <----- no sub and INVERSED
_____________________(object) set boolean false