Custom Tooltips

// Step 1 — Add a new page and mark it as a Tooltip page

// Right-click the page tab → Add page
// Name it descriptively: "Tooltip - Region Detail"

// Mark as tooltip page:
// Format pane (with nothing selected, or use the Page info panel)
// → Page information → Allow use as tooltip → ON
// → Canvas settings → Type → Tooltip
//   This automatically sets the page to a fixed small canvas size

// Recommended tooltip page canvas size:
// Width:  320px  (fits inside most visuals without overflow)
// Height: 240px  (compact but enough for 3–4 KPIs + one chart)

// Set canvas background:
// Format pane → Canvas background → Colour → #0f172a or #ffffff
// Dark backgrounds work well for tooltip pages — they stand out
// clearly from the main report background

// Set page size manually if you need a different size:
// Format pane → Canvas settings → Custom
// Width: 400, Height: 280  — for a larger tooltip with a chart

// Step 3 — Assign the tooltip page to a visual

// Option A — Automatic (report page tooltip)
// Power BI automatically offers your tooltip pages as options
// Select the visual → Format pane → Visual tab → Tooltips
// → Type → Report page
// → Page → select "Tooltip - Region Detail"

// All data points in that visual now use the custom tooltip

// Option B — Field-based (show a specific field value in tooltip)
// Format pane → Visual tab → Tooltips → Type → Default
// Drag extra measures to the visual's Tooltip field well
// The tooltip shows those measures alongside the standard values
// Use this for quick additions without building a full tooltip page

// Tooltip field well example — adding YoY % to a bar chart tooltip:
// Drag [Revenue YoY %] to the Tooltips well in the Values section
// Now hovering any bar shows: Region, Revenue, Revenue YoY %

// Which approach to use:
// Use Report Page tooltip when:
//   - You need charts or multiple formatted visuals in the tooltip
//   - The tooltip needs consistent branding and layout
//   - You need more than 3-4 values
// Use Field tooltip when:
//   - You just need 1-2 extra measures shown
//   - Quick addition with no layout requirement
//   - The measure format string is sufficient for display

// Dynamic tooltip header — shows the hovered context
Tooltip Header =
VAR Region  = SELECTEDVALUE(Orders[Region],  "All Regions")
VAR Year    = SELECTEDVALUE(Calendar[Year],  "All Years")
RETURN
    Region & "  ·  " & Year

// Use this measure as the title of a card or text box on the tooltip page
// When hovering North bar in a chart filtered to 2024:
// → "North  ·  2024"
// When hovering Total in a year-only chart:
// → "All Regions  ·  2024"

// Dynamic subtitle — adds extra context
Tooltip Subtitle =
VAR OrderCount = COUNTROWS(Orders)
VAR LatePct    =
    DIVIDE(
        CALCULATE(COUNTROWS(Orders), Orders[Status] = "Late"),
        COUNTROWS(Orders)
    )
RETURN
    TEXT(OrderCount, "#,##0") & " orders  ·  "
    & FORMAT(LatePct, "0%") & " late"
// → "142 orders  ·  8% late"

// Assigning the same tooltip page to multiple visuals

// Visual 1: Bar chart — Revenue by Region
// Format pane → Tooltips → Type: Report page
// → Page: "Tooltip - Region Detail"

// Visual 2: Map — Revenue by Region (filled map)
// Format pane → Tooltips → Type: Report page
// → Page: "Tooltip - Region Detail"

// Visual 3: Table — Region, Revenue, Orders (matrix)
// Format pane → Tooltips → Type: Report page
// → Page: "Tooltip - Region Detail"

// All three visuals now show the same rich tooltip
// when hovering any region — one page, three visuals

// Tooltip page scoping — what context is passed:
// Bar chart hover on North bar → Region = "North"
// Map hover on North territory → Region = "North"
// Matrix hover on North row → Region = "North"
// All three pass the same context — tooltip renders identically