Troubleshooting & FAQ

Symptoms first, then the fix. If your problem isn't here, get in touch.

The chart doesn't render

The landing page is still showing

The visual needs Party, plus one of Seat Count or Seat ID, before it draws anything. Check the Build pane — an empty well is the answer nine times out of ten.

Party is always required. Seat Count on its own, or Seat ID on its own, isn't enough.

"Seat Count must be a number"

The message reads:

Seat Count must be a number. Use a numeric measure or a count aggregation (for example, a count of the Seat ID field).

You've put a text column into the Seat Count well. The usual cause is dragging a Seat ID or Member column there, where Power BI defaults its aggregation to First — which returns text.

Fix: open the field's dropdown in the Build pane and change the aggregation to Count, or bind a real numeric measure instead.

The visual refuses to draw anything in this state on purpose: rendering the parties it could parse would produce a plausible-looking chart with the wrong totals.

"This chart can display at most 10,000 seats"

Your Seat Count measure adds up to more than 10,000 across all parties. See The seat limit — the practical fix is to scale the measure down (one dot per 10 or 100 units) and say so in the title, or to filter.

The chart area is blank

Every field is bound, no message appears, and nothing is drawn:

• The measure returns blank for every party. Drop the same measure into a table visual to confirm it produces numbers.
• A filter or slicer has emptied the data. Check the visual's filter card and the page-level filters.
• Every value rounds to zero. A measure returning 0.4 per party rounds to zero seats. Scale it up.

Seats and totals look wrong

The total is lower than it should be

In per-seat mode, the first thing to check is Seat ID uniqueness. If two parties both contain a seat numbered 1, one of them is dropped. Use a genuinely unique key — a member ID, or [Party] & "-" & [Seat No].

The second thing is Power BI's own row limits, which apply before the visual sees anything. For a large chamber, party totals mode sends a handful of rows instead of hundreds and sidesteps the question entirely.

The seat counts don't match my table

• Values are rounded to whole seats. 41.6 draws 42. Round in the measure if the totals must tie out exactly.
• Negative values are drawn as zero. A party can't hold minus three seats.
• Check the aggregation on the Seat Count field — a Count where you meant a Sum, or vice versa.

A party is missing entirely

A party whose seat count comes out zero or blank is drawn nowhere and gets no legend entry. That's deliberate: an empty wedge would be a gap in the arch. Check your filters, and check whether the measure returns blank rather than zero for that party.

Order and layout

The parties are in the wrong order

Without a Sort Order field, parties are ordered alphabetically. Bind a numeric Sort Order column — lowest value at the left end — and both the arch and the legend follow it.

Sort by column doesn't help here

Setting Sort by column on your Party column in the model does not change the arch. The visual sorts parties itself, by Sort Order if you bind one and alphabetically otherwise. This is the most common surprise for editors who use it everywhere else. See Seat and party ordering.

One party is in the wrong place, the rest are fine

That party has no Sort Order value, so it falls back to alphabetical placement relative to the others. Fill the column in for every party — including "Other", "Independent" and "Vacant".

The chart looks small and lost in its container

The arch is scaled to fit the space left after the legend, so its aspect ratio and the container's need to agree:

Container shape	Try
Wide and short	A wider arc (200–260°), legend Bottom center
Roughly square	Arc 180°
Tall and narrow	A narrower arc (120–150°), legend Top or Bottom

Turning the legend off, or switching Show Total Seats off, both give the arch more room.

The number in the middle is very small

The centre label is sized to the empty space inside the arch. With few, large seats — a 12-seat chart, say — the hole is small relative to the dots and the number shrinks with it. A wider arc enlarges the hole; so does adding more seats.

If it's missing entirely, check Format → Layout → Show Total Seats.

Can I make the seats bigger, or add more rows?

No — rows, seat size and spacing are all derived from the seat count and the arc. To make the dots bigger, either reduce the number of seats (scale the measure) or make the visual container larger.

Colours

A colour picker does nothing

You have a column bound to Custom Color. It takes priority over the Data Colors pane for every party where it has a value. Either clear the field well, or blank the colour for the parties you want to control from the pane.

See the three-tier resolution.

Colours changed when I used a slicer

Palette colours are handed out in the order parties first appear in the data, so removing a party shifts the colours of the ones after it. Pin the colours you care about with the Custom Color field or the Data Colors pickers.

My Custom Color column is being ignored

• Values must be CSS colour strings — #DC241F is the safe form. A bare DC241F without the # won't work.
• The column must be text, not a number.
• Blank rows fall through to the pane or the theme palette, so a partially-filled column gives mixed results.

Every seat is the same colour

Windows high contrast mode is on. The visual takes the system palette and draws every seat in the foreground colour — see High contrast. Your colours are kept and return when it's switched off.

Legend

Legend entries are truncated, or show only numbers

With Seat counts on and not much width, party names are shortened with an ellipsis so the number stays complete; when there's no room for a name at all, only the count is shown. Fixes, in order of effectiveness:

1. Move the legend to Right or Right center — a vertical legend gets far more width per entry.
2. Reduce Text Size.
3. Shorten the party names in the model.
4. Turn Seat counts off.

The legend has scroll arrows

There are more entries than fit. Move it to a side position, reduce the text size, or group small parties into "Other" in the model.

The legend disagrees with the arch

It can't — both use the same order and the same counts. If they look different, you're probably comparing the legend to a different visual's numbers, or to a table that hasn't got the same filters applied.

Interactivity

Clicking a party doesn't filter anything

• Check Edit interactions. On the Format ribbon, select the Parliament Chart, choose Edit interactions, and make sure the target visuals aren't set to None.
• Dashboard tiles and some read-only hosts disable selection — that's Power BI, not the visual.
• Make sure you're clicking the chart, not the centre total, which deliberately clears the selection.

Cross-highlighting from another visual doesn't dim the seats

You're in per-seat mode with no measure in the Seat Count well. Add one — Seats = COUNTROWS ( 'Members' ) — and the dimming starts working. The chart's size is still driven by the rows. See Being filtered by other visuals.

Selecting another visual shrinks my chart instead of dimming it

That visual's interaction is set to filter rather than highlight. Format ribbon → Edit interactions, then pick the highlight icon over the Parliament Chart. Highlight is usually what you want for a seat chart, since the total is meant to be fixed.

My tooltip field doesn't appear

• Is it a measure? The Tooltips well is categorical and takes columns only. Use a report-page tooltip for measures.
• Is the same column also in Seat ID? Bind a duplicate column instead — a column carrying both roles is read as the seat key.
• Is Format → Tooltip → Show on?

The first tooltip row says "Party" but my column is called something else

That row is always labelled Party. The rows below it use your own field names.

Licensing

A "License Required" notice appears on the visual

The visual is unlicensed for the current user. Every feature still works — the notice is the only difference. See Licensing & support.

It's never shown on the landing page, and never included in PDF or PowerPoint exports.

My license key says it's invalid

Check the status line meanings — the message distinguishes a malformed key, an expired one, a key for a different ChartPad product, and a Report Server without HTTPS.

FAQ

Can the chart draw a majority line?

No. Put the threshold in a card visual beside the chart — INT ( total / 2 ) + 1 — or use Sort Order to group a coalition's parties together so the block reads as one arc. See Coalition and majority scenarios.

Can I put a gap between parties?

No. Wedges are contiguous, which is what makes the total countable. A "Vacant" or "Independent" party in a neutral grey, placed with Sort Order, gives a visual separation that's also honest about what's in the gap.

Can I show two measures — current and projected?

Not in one chart; only one Seat Count measure is read. Use two Parliament Charts side by side with the same Sort Order and colours, or a field parameter to switch the measure.

Can I label individual seats with names or numbers?

No — seats carry no text. Use one row per seat with a Tooltips field so hovering names the seat, and pair the chart with a table visual for the full list.

Can I change the seat shape, the hole size, or the number of rows?

No. Seats are circles, the hole is a fixed proportion of the arch, and rows are calculated from the seat count and the arc. The Arc slider is the one geometric control, and it changes all of these indirectly.

Does it work in Power BI Report Server, Embedded or Publish to web?

Yes. AppSource licensing isn't available there, so use a direct license key instead. On Report Server, key verification needs HTTPS.

Does it export to PDF and PowerPoint?

Yes. The visual is Microsoft-certified and reports its render status to Power BI, so exports and email subscriptions wait for the chart to finish drawing. The license notification is never included in an export.

Is any of my data sent outside Power BI?

No. The visual is Microsoft-certified, which means its code has been reviewed and confirmed to make no external calls. Even license-key verification happens offline, inside the visual.

How many parties and seats can it handle?

Up to 10,000 seats in party-totals mode. Readability is the tighter limit: keep parties to about 12 and seats to a few hundred, or the wedges and dots stop being distinguishable.