The dropdown menus in the new visualization GUI (RapidMiner 9.2+) do not react correctly on arrow keys (up and down).
In the former versions of the GUI, it was possible to "go" overall values of the attribute just by pressing the arrow key on the keyboard in order to see how each value impact the graph.
However, in the current release of RapidMiner, the dropdown menus react correctly only when I make the dropdown menu active with the tabulator key.
If I select the dropdown menu with the mouse, the arrow keys are ignored (the GUI refreshes itself (at least the controls in the Plot group), menu "rolls up" and the "focus" gets lost).
The workaround: Rely on the mouse.
Possible solution: Do not refresh the list of the controllers after an event originating from the mouse (the GUI does not "flick" when I change the selection with the keyboard).