Vega: Condition based on drop down value

Thank you @aaron-nimocks

One of the drop down value must be All, to display all the data. And also I am not able to add the legend, legend must be month so that we can easily understand, in which month that incident has been logged. If not legend, we must be able to plot that month name along with year on X-axis.

Can you please help me with the above requirement.