Splashtop can't handle Little Snitch dialogs
I run Little Snitch on all of my Macs to monitor outbound Internet connections from apps and macOS processes. When a Little Snitch dialog pops up in a Splashtop Streamer window, it's frozen on the screen. I can't click any menu or button. I also can't move the dialog.
When that happens on another Mac on my LAN, I can use macOS Screen Sharing to take care of Little Snitch. So far, I haven't encountered this Splashtop showstopper on a distant, unattended Mac. But I expect it's only a matter of time because I've recommended Little Snitch to many of my clients.
P.S. Here's an example of a Little Snitch dialog on my LAN file server: