Recently, JOSM developers introduced a new feature in the panels. Now, the buttons usually displayed on the bottom of almost all JOSM panels are invisible until you move the mouse on their expected location on the screen. This makes a nice effect I call the "ugly christmas lights" where you have a lot of animations on the screen when you just move the mouse cursor around.
I already did not like the highlighting of OSM elements when you just moved the mouse over OSM ways or nodes, without speaking about the unnecessary, useless mouse cursor changing itself which introduced a lot of instabilities/bugs in JOSM for a while.
I like christmas trees and christmas lights but only during one week in december not during my OSM edits sessions the whole year. I just wanted to say that current trend of JOSM user interface design is not my type.