Missing includes in Chart configuration when the main source of data changed

Hello,

I am using a data source for every month. Knime generated a list of variable name according to the data source. Finally these variables using a create a bar chart.

When I change the data source from another month, Bar chart configuration both previous month variables as “MISSING…” and actual months variables like the picture below

Are there any method to eliminate these missing tagged variables automatically.? Otherwise I have to do this manually for every month.