I have a combo chart (area and line, or any other types which can overlap), but I can not grab and drag the datapoints! What is going on?
Please first make sure that you are not trying to drag data which are connected to formulae, as they cannot be modified with dragging.
If the data is not connected to formula, it can happen that one Series overlaps the one you are trying to drag. Please inspect the Series information on the Task Pane, under the Chart section, and modify their order to have your desired Series in the front! The Series’ color can give you a hint, if they differ in the Legend and on the Chart Area – rearranging might be necessary.