Whenever I switch from the new Domino Designer (Eclipse IDE) to the Notes Client, the sidebar loses its setup of which panes were minimized/maximized/set to a particular size. I can restore them, but it’s slightly annoying.
Also, I notice that within the Eclipse IDE the useful old trick of putting a Notes formula into a text field and pressing Shift + F9 to calculate the formula (often useful for debugging hidden fields, lookups etc.) no longer works. It seems a shame.