API to define tooltips for Grid header cells

[glebfox]

Describe your motivation

The most common case is when the header text doesn't fit the column width and is truncated. Users then want to hover over it to see the full text.

Describe the solution you'd like

Either API similar to tooltipGenerator for body cells or a simple setTooltip method.

[rolfsmeds]

As a workaround, you can use a component (e.g. a Span) in the header cells and apply a tooltip to those instead.

Alternatively, you could wrap the text in the header cell with white-space: normal, although I'm not 100% sure if this works without issues, but you'd do that with the ::part(header-cell) selector.

[jouni]

Ideally, such a tooltip would only be shown when the text is actually truncated. But that’s hard/impossible to detect with JS/CSS.