Explorer Mode works smoothly for dragging tokens, but buggy when moving with arrow keys

I've been experimenting with setting up a large dungeon with lots of dynamic lighting lines to see whether it would be feasible to run with Explorer Mode turned on. During my testing, as I moved the token around, it would appear to work fine for a while, then I'd begin to get buggy behavior as the Explored, but no longer Visible, areas would continue to update randomly, for literal *minutes* after I had stopped moving the token. If I continued moving the token for longer, eventually the Explored area would stop updating at all for the newly Explored regions--that is, nothing new would get added to the Explored region, but old Explored regions would continue to oscillate (randomly?) between Explored and Unexplored. Anyway, I was about to conclude that Explorer Mode just wouldn't work for a dungeon of the size I was working on, when I noticed that I didn't seem to be getting the same behavior if I moved the token by drag-and-drop--all of my testing up to that point had involved movement with the arrow keys, which is my preferred method. I reset the Explored region and retested using just drag and drop movement. I was able to explore the entire dungeon, and I had absolutely no bugs with Explorer Mode . The Visible and Explored areas updated entirely smoothly, except for one minor visual hiccup, which appeared for a second and then disappeared never to recur (it looked like a bit of lag rendering a newly visible area).  Any ideas why this behavior is occurring? If anything, I would have expected drag and drop to be laggier, since it apparently updates vision and exploration across numerous points along the path of movement, whereas arrow key movement could potentially just update it at the destination location. What is going on with this? I have not seen this mentioned elsewhere, so I also report it in hopes that it might point devs in the right direction for resolving the difficulties people continue to report with UDL Explorer Mode.

Interesting. Did you experiment with toggling Update on Drop?

keithcurtis said: Interesting. Did you experiment with toggling Update on Drop? I found that I was getting more buggy behavior with Update on Drop enabled. After more testing, I think the reason for this is because in order to explore the map with Update on Drop enabled, you have to drop the token more often. To confirm this, I turned off Update on Drop, and started exploring by making numerous quick, 1-square moves using drag and drop. Pretty soon, performance was just as bad as I had observed with arrow key movement. My hypothesis is that there is some routine that gets called every time the token stops moving--i.e., whenever you drop the token in drag-and-drop, and whenever the token moves a space because of a keystroke input. When you get too big a stack of those function calls, the problematic behavior starts. So the observed behavior that keystroke movement is worse for Explorer Mode than drag and drop movement seems to be a result of the fact that keystroke movement almost always involves more of these "stops." What's interesting is that there seems to be a *different* routine that is getting called to dynamically update vision/exploration *during* a drag. I don't think I ever observed any significant buggy behavior while dragging--only after dropping the token. In fact, there were definitely times when the VTT correctly updated an area to Explored while I was dragging the token, but then incorrectly reverted it to Unexplored when I dropped the token later. Thoughts?