Master Calendar Not working when I use filter

[zelalemdatew]

Hello

I used a master calendar so all months in the bar chart will display regardless of the values. The problem is when I select a specific value from the filter pane, the the months with zero values do not show in the bar chart.  The first image below show all months (the desired result) and the second image shows missing months when selecting from the filter pane. 

the expression I used to get the values (Y axis) is:  =Rangesum(Above(Count(distinct PatID),0,rowno())) and for X axis I am using =MonthYear from the master calendar. Can anyone please help me how I can address this issue? Appreciate any help.