Hi Jean,
Thanks for the comprehensive reply!
I must admit I've never had issues before when the FSM I'm targeting in an action is the only FSM on the gameobject in question, as is the case here. Regardless, I tried adding the FSM name, and somehow this seems to fix the issue with the array list that was getting wiped by these actions, but the drag/drop elements still aren't getting modified by the 'set property' actions.
Sorry, I don't think I've done a very good job of explaining what I'm trying to achieve. The line I described previously is not an actual onscreen line, but instead the 'line' I was describing is simply the path of the user's mouse (or, as the target platform is android/ios, the path of the user's touch).
The only onscreen line I'm using is simply to display the links built between each of the grid items. I've attached a video here displaying the concept. I've managed to get it partly working using UI Pointer Down/UI Pointer Enter/UI Pointer Up, but I can't seem to direct UI Pointer Up to the correct object (ie the object under the mouse when the pointer goes from down to up). This is what I was hoping to achieve with the UI drag/drop function.
I tried using triggers initially, but had issues with the mouse down and mouse up not being registered on UI elements (which my grid is made up of). I'll have another look at getting this working using mouse up/down together with trigger enter 2d, but as I will be using touch input ultimately, and my game is only UI, I thought it best to stick to the UI input functionality.
I'm open to taking a different approach, but I need something that can easily be tested on mouse while I develop, then ported to touch input when the time comes. I look forward to hearing your input!
Thanks in advance,
Steve