change color conditional in chart

[#1]

I want change color if selected Accounting Period (AP)  is greater than current AP in Chart, but my implementation does not work, in the graphik example it should change from yellow to red if AP_KEY is greater or equal 27, see example app.
Background color property of expression:

=

IF(DSS_DATE.AP_KEY>=$(=DSS_DATE.AP_KEY) ,Red(),Yellow())

[#2 · Accepted solution]

The Solution, with the help of Community Collegus from another similar topic.see attached ap

The Formula which solved the problem was:

=IF(ONLY({<DSS_DATE.AP=,DSS_DATE.F_YEAR=>} DSS_DATE.AP_KEY) <= MAX(TOTAL DSS_DATE.AP_KEY), '<S1>','<S3>')