fix: Fixes pie chart tooltip placement in Firefox (#62)

* fix: Fixes pie chart tooltip placement in Firefox

* Update chart-extra-tooltip.tsx

Author: pan-kot

src/core/chart-api/chart-extra-tooltip.tsx

@@ -198,7 +198,8 @@ function getPieChartTargetPlacement(point: Highcharts.Point): Rect {
   // Instead, there is a `tooltipPos` tuple, which is not covered by TS.
   // See: https://github.com/highcharts/highcharts/issues/23118.
   if ("tooltipPos" in point && Array.isArray(point.tooltipPos)) {
-    return { x: point.tooltipPos[0], y: point.tooltipPos[1], width: 0, height: 0 };
+    // We use very small but non-zero track size as otherwise it is placed incorrectly in Firefox.
+    return { x: point.tooltipPos[0], y: point.tooltipPos[1], width: 0.1, height: 0.1 };
   }
   // We use the alternative, middle, tooltip placement as a fallback, in case the undocumented "tooltipPos"
   // is no longer available in the point.