Showing only record with valid key value

[jack]

I have a list box , based on clicks it  will show records

but when list box is not having a click set

all records with standard key-value 'X' are in chart , in other type off charts would be ok, bit this chart should stay empty

if  from list box B/F/I/K   is not  activated

how to set in the chart a exclusion for records with key  value X  anyway