Displaying Chart with 0 results clears the year field

[#1]

I am very new to Qlikview and have learned enough to be dangerous the last couple of weeks.  It is probably something fairly easy but I can't seem to figure it out.  I have a button object which main objective is to maximize a chart object while minimizing another chart object.  The chart is just displaying a list of patients who did not get a certain test done on a visit for this current year.  It works just fine until your selection criteria doesn't have any results.  When that is the case it clears the selection criteria for the year so it does display results just not from the current year.  Is there a way to prevent that from happening.  Hopefully I described that well enough.

Thanks in advance for any help you provide.

[Digvijay_Singh]

Do you want to protect your chart to change from filters selection? If Yes, then you need to use set expression in your chart expression so that it will always show the same results irrespective of your selection of one or many fields in the filters.

[#3]

Is there some reason the chart won't display a blank chart or just state no results or something like that?  Why does it change the selection if there isn't any results?

Where do you put this set expression?  I found this link explaining it a little bit but not where in the object definition it is defined.

http://help.qlik.com/en-US/qlikview/12.1/Subsystems/Client/Content/ChartFunctions/SetAnalysis/set-an...