Filter visual by date without changing measure

Hello,

I have a graph of earnings with columns for monthly earnings and a measure for running total earnings, displayed on the graph as a line. I want to be able to have the visual display just months within the last year, but when I deselect any months in the filters pane it deducts their earnings figures from the value of the total earnings measure. I understand that this is because the measure evaluates in the current filter context. So how can I achieve what I'm looking for? Is it that I need to change the DAX of my measure to ignore that part of the filter context? Would I do that by using ALLSELECTED or something similar? The code for my measure and an image of the graph are below. 

Thanks for your help.

Total Earnings = 
CALCULATE(
	[Monthly Earnings],
	FILTER(
		CALCULATETABLE(
			SUMMARIZE(
				'Date Table',
				'Date Table'[Year Month Number],
				'Date Table'[Year Month]
			),
			ALLSELECTED('Date Table')
		),
		ISONORAFTER(
			'Date Table'[Year Month Number], MAX('Date Table'[Year Month Number]), DESC,
			'Date Table'[Year Month], MAX('Date Table'[Year Month]), DESC
		)
	)
)