(1) Do "Toggle input method" -> "Edit" -> "Insert". Observe undefined-variables.png.
(2) After "Toggle input method", add one item and a macro to the expression. Then, delete the item. The frontend displays an error, but the item is still there. See item-still-there.png.
(3) The condition wizard should be improved. For instance, see wizard-improvement.png. The function description mentions T, but T does not appear as one of the input fields. "Last of" does not sound very well. Some function descriptions, like "Find string T last value", should be improved. Finally, some function descriptions have a dot at the end, some do not.