I have a data set with a time variable (month), two numerical variables (population of wildebeest and rainfall) and a categorical variable (location).  I want to get 3 side-by-side graphs, one for each location, with time on the X-axis and 2 Y-axes.  I find that the order in which I manipulate the graph matters.  I get what I want if I plot the X-axis and the 2 Y-axes BEFORE creating the side-by-side graphs with the categorial variable.  However, if I plot the X-variable and one Y-variable, then create the side-by-side graphs, then try to add the second Y-variable, I only get points plotted for one of the side-by-side graphs.  Screen shot attached.  Bug?