Last date label hidden on Time Series X-axis

[aijung0331]

In Charts, when the X-axis is set to a Time format, the last date label often fails to display.
This is particularly important for daily or hourly monitoring dashboards where the user needs to confirm the exact "latest" time reflected on the chart at a glance.

[dosubot[bot]]

Hi @aijung0331! I'm Dosu and I’m helping the superset team.

This is a reported issue that has been addressed through several recent fixes. The root cause is ECharts' hideOverlap: true setting aggressively suppressing the last label when it detects potential overlap at the axis boundary [1] [2].

Several PRs have landed to fix this:

• PR #37755 — conditionally disables hideOverlap for time-based axes with rotated labels and adds dynamic right padding proportional to the rotation angle [1]
• PR #38017 — fixes the smart date formatter so forced max labels don't render as raw timestamps [3]
• PR #38733 — deduplicates X-axis labels that could appear twice at axis boundaries [4]

If you're on an older version and can't upgrade yet, some workarounds:

• Rotate the X-axis labels (e.g., 45°) — this gives more space and triggers the hideOverlap: false logic in newer builds
• Set "X Axis Label Interval" to "All" in the Customize panel (though this may not work reliably for timestamp columns [5])
• Increase chart width to reduce label crowding

Upgrading to a version that includes these PRs (merged Feb–Mar 2026) should resolve the issue.

To reply, just mention @dosu.

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[aijung0331]

@dosu.

For our use case (monitoring dashboards), ensuring that the last timestamp label on the time axis is always visible is not just a visual preference, but a functional requirement. The final data point represents the most recent state, and if its label is hidden, it can lead to misinterpretation or reduced usability.

Given that:
The current behavior is still dependent on ECharts’ internal overlap handling, and
There is no deterministic configuration (e.g., showMaxLabel) exposed to guarantee this

I’d like to ask:
Is there any plan or possibility to introduce a deterministic solution for this?

For example:
Exposing a showMaxLabel-like option in the chart controls, or
Ensuring the last label is always shown for time-series charts regardless of overlap logic

Relying on label rotation as a workaround is not always acceptable from a UX perspective, especially for dashboards where readability and consistency are critical.
Additionally, in practice, even with label rotation applied, the last label may still not be shown in some cases, so this workaround does not reliably solve the issue.

Appreciate your thoughts on whether this could be addressed in future updates.

[dosubot[bot]]

That's a very reasonable request, and I understand why this is a functional requirement rather than a cosmetic one for monitoring dashboards.

To answer your question directly: I found no open feature request or roadmap item specifically for exposing a showMaxLabel-like control on time-series charts. The showMaxLabel approach has a troubled history in the codebase — it was implemented, then reverted (PR #24995), and subsequent 2026 fixes evolved away from it due to issues with "phantom labels" appearing at axis boundaries with no corresponding data points [1].

That said, there are a couple of paths worth knowing about:

Theme-level overrides (available now, requires admin access): Superset 6.0+ supports echartsOptionsOverridesByChartType in the theme configuration, which can apply ECharts settings globally to specific chart types [2]. This could potentially be used to inject showMaxLabel: true for all time-series charts without modifying plugin code. This is likely your most practical option if you control the Superset deployment.

ECharts Options JS editor (partial, not yet for time-series): Superset 6.1+ introduced a per-chart "ECharts Options (JS object literals)" editor for "Evolution" chart types (bar, area, line, etc.), which allows direct customization of axis properties [3]. However, this has not been extended to Time-Series charts yet. If it were, you could pass showMaxLabel: true on a per-chart basis — so this is a feature gap worth advocating for.

Dataset-level workaround: Some users have worked around the timestamp-specific limitations by casting the date column to a STRING type at the dataset level and then using "X Axis Label Interval → All" [4]. This bypasses ECharts' time-scale overlap logic entirely, though it changes how the axis behaves.

Given the functional importance of this for monitoring use cases, filing a feature request to either (a) extend the ECharts Options JS editor to time-series charts, or (b) add a dedicated "Always show last label" control, would be well-motivated. The infrastructure for both approaches partially exists — it's a matter of extending coverage to time-series chart types.

To reply, just mention @dosu.

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[aijung0331]

@dosu.

While I appreciate the suggestions, from a production-monitoring standpoint, the current gaps remain unresolved:

Theme-level overrides & Dataset workarounds: These are "global" or "destructive" fixes. We need a per-chart, granular control that doesn't force us to change our data schema (casting to STRING) or affect every chart in the organization.

ECharts Options JS Editor: You mentioned this is the most promising path but is currently a feature gap for Time-Series charts.

To move this forward and get a clearer commitment on the roadmap, I have three specific questions:

1. Is there an active RFC (Request for Comments) or SIP (Superset Improvement Proposal) for extending the ECharts Options JS editor to Time-Series charts? If so, could you provide the link so we can track it?

2. Could this be prioritized as a "Feature Parity" task? Since the JS editor already exists for Evolution charts, bringing it to Time-Series seems like a logical next step rather than a from-scratch feature.

3. What is the formal process to escalate this as a "Functional Requirement" for monitoring? We would like to ensure this is not just logged as a "visual preference" but as a blocker for high-precision dashboarding.

If a specific release version (e.g., 6.2 or 7.0) is not yet confirmed, could you at least confirm if this "JS Editor extension" can be added to the Backlog for the next development cycle?

Looking forward to a more definitive update on the timeline.

[aijung0331]

@dosu.

[aijung0331]

@dosu.
Friendly bump on this thread. We are keen to know if there's any active SIP or backlog planning regarding the ECharts Options JS editor for Time-Series charts. Any feedback from the dev team would be highly appreciated!