Testing out the lighting and I am a person who presses CTRL+Z a lot. Found out pretty quick today that if you've placed a bunch of lights, pressing ctrl Z once, will take all the lights last placed, and set their Bright and Dim values to very small values. At first I thought it was just loosing a decimal place. But no it's not that simple.
TLDR; I expected CTRL Z to remove the last placed light or to change it's settings back one change from what I had just done. What it instead had done was change the settings on all previously placed lights. (It also removed their presets!)
(side note for debugging purposes: If I placed some lights and then switched to doing line of sight functions and then went back to lights. Control Z after that would change only the lights after I had touched LOS, or other functions.)

I have to stop myself from reflexively hitting CTRL Z but overall the rest is very well implemented! Great work~!