Add Model‑Level Control for Excel Drill‑Through in Direct Lake Models

[101Mathew]

Problem

The recent addition of Excel Drill‑Through support for Direct Lake models is a welcome improvement. However, this change introduces a significant governance and usability challenge for large enterprise models.

In the current implementation:

• Drill‑through is enabled by default for every measure

• The default behavior exposes all columns from the underlying fact table

• The only way to control this is to manually add a detailRowsDefinition to each measure

For large Direct Lake models with hundreds or thousands of measures, this is not scalable. We would prefer a governance model where drill‑through is disabled by default, and only specific, approved measures opt in.

Current Pain Points

To achieve controlled drill‑through today, we must:

• Edit every measure

• Add a “blocked” detailRowsDefinition for measures that should not allow drill‑through

• Add a custom detailRowsDefinition for measures that should allow it

This is extremely time‑consuming and error‑prone at scale.

Additionally, the default Excel drill‑through behavior (showing all fact table columns) is rarely appropriate for governed semantic models and cannot currently be changed.

The only workaround is to:

1. Export the model as TMDL

2. Bulk‑edit all measures using scripts or AI

3. Re‑import the updated TMDL

This is not a sustainable long‑term approach.

Requested Enhancements

1. Model‑level setting: “Disable drill‑through by default”

A simple toggle in Power BI Desktop or the model properties pane that allows developers to invert the default behavior:

• Off by default → Measures must explicitly opt in

• On by default → Current behavior

This would immediately solve the governance issue for large models.

2. Ability to define a default detailRowsDefinition

Allow model authors to specify a default drill‑through template or suppression rule, rather than relying on the fact‑table dump.

3. Optional: UI support in Power BI Desktop

For example:

• A model‑level drill‑through policy setting

• A bulk‑apply option for detailRowsDefinition

• A “block drill‑through” checkbox in the measure properties pane

These additions would make drill‑through governance far more manageable.

Why This Matters

Direct Lake is designed for very large, enterprise‑scale models. These models often require strict governance, and the current drill‑through defaults create:

• Data exposure risks

• Inconsistent user experiences

• Significant manual overhead

Providing model‑level control would align drill‑through behavior with enterprise needs and reduce unnecessary TMDL manipulation.

For reference, here’s the update announcement:

Drillthrough in Excel now supported for Direct Lake and DirectQuery Models | Microsoft Power BI Blog...