I notice that v19 of SE changed some behavior that I liked in v18.
In the left side of Slickedit, I have my tool windows "Projects/Defs/Class/Symbols/Open/Files". They all occupy the same pane and I choose which one I want based on the tab.
In SE v18, if I made this left pane take up less horizontal space, each of the tabs would shrink, so that they were each visible, but some of the text would disappear (which was fine).
In v19 the tabs no longer shrink when the left pane is made horizontally smaller. Instead there are new "arrow" keys to scroll across the tabs.
I've attached some pictures to illustrate what I am talking about.