Descriptive Problem Summary:
Mouse interactions with any plane_master is messed up. What I'm doing in my case is using an obj called map_zoom as a plane_master, creating it in the client_sceen and animating() to zoom in the icons. I prefer doing that instead of zooming the icon_size to prevent HUD objects from moving as well.
The issue is when interacting with the world using the mouse, the elements are all wrong and the mouse interacts as if it's hovering on the objects BEFORE they were zoomed in. For ex, in this screenshot, my cursor was on the player but in the statusbar it says: "Wall"- which means its still interacting with what was previously a well before I zoomed in.
Code Snippet (if applicable) to Reproduce Problem:
var/obj/map_zoom/Z = new()
client.screen += Z
animate(Z, transform = matrix()*client.iconsize, time = 4)
appearance_flags = PLANE_MASTER
screen_loc = "1,1"
plane = 0
Mouse interacting with the right elements.
Mouse interacts with the wrong elements after zooming in.
This looks like a previous bug report that you fixed - and that I can't find related to mouse clicks :/