Unable to filter Top-N using parameters.

Hi abhi201002 ,

Thanks for the clarification, what you’re seeing is due to how evaluation context is affecting your measures. The main issue is the use of ALLSELECTED() in your RANKX, which makes the ranking dependent on the current filter context rather than the full customer set. As a result, the rank gets recalculated inconsistently (e.g., collapsing to only 1 customer at 100%, all 0s below that, and partial results above 100%).
Additionally, using a measure (Dynamic Filter) that depends on rank as a visual-level filter creates a feedback loop where the filter and ranking influence each other. Your expectation (Top 5 for 5%, Top 50 for 50%) is absolutely valid, but it requires ranking over a stable, unfiltered dataset. You can partially improve this by replacing ALLSELECTED with ALL, but for consistent and scalable results, the TOPN-based approach is recommended as it avoids these context issues entirely.

The TOPN based approach works by calculating the TopN customers in a separate virtual table, instead of relying on ranking inside the visual. First, you convert your percentage slicer into a number of customers:

Top N Customers =
VAR Pct = SELECTEDVALUE('%Top Customer'[%Top Customer], 1)
VAR TotalCust = DISTINCTCOUNT(Orders[Customer ID])
RETURN
MAX(1, INT(Pct * TotalCust))

Then, you build a virtual table of the top customers using TOPN:

TopN Filter =
VAR N = [Top N Customers]
VAR TopTable =
TOPN(
N,
ADDCOLUMNS(
VALUES(Orders[Customer ID]),
"@Sales", [Total Sales]
),[@Sales], DESC)
RETURN
IF(
ISINSCOPE(Orders[Customer ID]) &&
Orders[Customer ID] IN TopTable,
1,0)

Finally, apply TopN Filter = 1 as a visual-level filter.

If further assistance is still required. 

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Best Regards,
Chaithra E.