Refer to the long red arrow in the attached screenshot, when the focus is in the "Language sets" group box, pressing the Alt+U key combination will not trigger the "Move Up" button at the right side, instead, the "Undo Changes" at the bottom of the dialog is triggered (notice that both interfaces feature the (U) key combination hint).
Another similar issue is featured in the left-up pointing short arrows, where there are multiple Alt+M keybinding hints are available in the same focused interface. In this case the Alt+M key combination triggers the "Move down" button at the right side.
In the en locale this issue is not reproduced.