Create bookmark with dynamic previous month

[TomBond77]

Hi experts

I have a variable which defines the previous month of a selected month: =Date(addmonths(max([Timestamp.autoCalendar.YearMonth]), -1), 'YYYY-MMM')

I tried to define a filter pane with this logic: =[Timestamp.autoCalendar.YearMonth]=$(vPreviousMonth)

But I am getting this syntax error:

Later on I would like to use the selected value as default bookmark.

Any ideas how to fix the syntax error?

Thanks, Tom

[marcus_sommer]

You may try: 

[Timestamp.autoCalendar.YearMonth]='$(vPreviousMonth)'

[TauseefKhan]

check with this:

= {< [Timestamp.autoCalendar.YearMonth] = {"$(vPreviousMonth)"} >}