Sheet Header - Nextedy Documentation

The header sits at the top of a sheet, next to the toolbar, and states which slice of data you are looking at — a title, a subtitle, and an icon. Because each can be computed from the current document, project, and URL parameters, one configuration used across many variants or projects tells you at a glance that you are on the right one, without going back to Polarion to check. Each of the three is either a static value or a single dynamic value expression (() => …). They are top-level keys in the sheet configuration, alongside sources, columns, and views:

title:    "Requirements"
subtitle: "() => context.project.name"
icon:     "Table"

The three fields

Key	Type	What it shows
`title`	`string` \| `() => …`	The primary heading. Falls back to the document name when it resolves to nothing (see Fallback and suppression).
`subtitle`	`string` \| `() => …` \| `false`	A secondary line above the title. Defaults to the document name when a `title` is set; `false` (or an expression resolving falsy) hides it.
`icon`	`string` \| `() => …` \| `false`	A glyph or image shown beside the title. Defaults to the `table` glyph; `false` (or an expression resolving falsy) is the only way to show none.

Evaluation context

A () => … header expression receives the same context object as other dynamic values, so the header can be driven by the sheet’s surroundings. The fields most relevant here:

Expression	Resolves to
`context.name`	The current document (configuration) name — the same value the header falls back to.
`context.project.name`	The Polarion project’s display name. Optional: a project may expose only its id, in which case this is absent.
`context.project.id`	The Polarion project id.
`context.parameters.<name>`	Any value present on the sheet’s URL query string, by the name it was given.

For the complete object see Context Expressions. Reading a value from the URL is covered under URL Parameters.

Build any surrounding text inside the expression — the whole value must be a single () => … for it to be evaluated. Concatenate or use a template literal (() => `Type: ${context.parameters.subtype}`) rather than mixing literal text with an expression.

Icon values: glyph or image

The icon value is classified automatically by what it contains:

A name made up only of letters and digits — for example Table, AspectRatio, World — is a Fluent (MDL2) glyph, rendered by name.
Any value containing a /, :, or . is treated as an image source and rendered as an <img>. That covers every practical image form:

Value	Interpreted as
`AspectRatio`	Fluent glyph, by name
`/polarion/icons/avatar/admin/avatar.png`	Image — a root-relative Polarion (or app) asset path
`https://cdn.example.com/icons/worksheet.png`	Image — an absolute URL
`data:image/svg+xml;base64,PHN2Zy8+`	Image — an inline data URI

The rule is purely the presence of a /, :, or ., so even a bare filename with an extension (worksheet.png) is taken as an image rather than a glyph. If an image source fails to load, the icon is simply omitted rather than showing a broken-image placeholder.

Fallback and suppression

Each field decides independently what to show when it is omitted or resolves to nothing. An expression that resolves to a falsy value (false, null, "", undefined) suppresses the field — it never prints the literal text false.

Field	Omitted	Resolves falsy	Explicit `false`
`title`	Document name	Document name (never a blank heading)	— not supported; `title` takes no `false`
`subtitle`	Document name if a `title` is set, otherwise nothing	Hidden	Hidden
`icon`	The `table` glyph	Hidden	Hidden

Two consequences worth noting:

Because icon defaults to the table glyph, icon: false is the only way to render a sheet with no icon.
A title that evaluates to empty behaves exactly like an omitted title: the document name becomes the heading, and (unless you set a subtitle) it is not also repeated as the subtitle.

Worked example

This RTM configuration varies all three fields by a subtype URL parameter, so …&subtype=electrical and …&subtype=mechanical open the same sheet under distinct, self-describing headers — while a plain link with no subtype falls back to the document’s own name and the default icon:

icon: >
  () => {
    switch (context.parameters.subtype) {
      case 'electrical': return 'AspectRatio';                                 // Fluent glyph
      case 'mechanical': return 'World';                                       // Fluent glyph
      case 'absolute':   return 'https://cdn.example.com/icons/worksheet.png'; // absolute URL -> image
      case 'relative':   return '/polarion/icons/avatar/admin/avatar.png';     // Polarion asset -> image
      default:           return 'table';                                       // fallback glyph
    }
  }

subtitle: "() => context.parameters.subtype ? context.project.name + ': ' + context.name : false"

title: "() => context.parameters.subtype ? `Type: ${context.parameters.subtype}` : context.name"

With …&subtype=electrical the header reads Type: electrical over a project-and-document subtitle, beside the AspectRatio glyph. Open the same sheet with no subtype and the subtitle’s expression resolves false (so it is hidden), the title falls back to the document name, and the icon defaults to table.

Dynamic Value Expressions

The () => … syntax used by all three header fields.

URL Parameters

How context.parameters.<name> values reach the header from the sheet’s URL.

Context Expressions

The full context object a header expression can read.

Open a Scoped Sheet with URL Parameters

A task that reflects a URL parameter in the header.

​The three fields

​Evaluation context

​Icon values: glyph or image

​Fallback and suppression

​Worked example

​Related

Dynamic Value Expressions

URL Parameters

Context Expressions

Open a Scoped Sheet with URL Parameters

The three fields

Evaluation context

Icon values: glyph or image

Fallback and suppression

Worked example

Related