[TooltipContext] Tooltip locked from onclick loses its data on touch, and the lock can't be released #922

Hi!

Repro here (open the repro as separate page and open devtools for it or open on the actual phone - even better)

tl;dr:

• Expected behaviour: first tap pins the tooltip, second tap unpins it.
• Actual: the tooltip vanishes right after the first tap, locked: true stays, next taps do nothing.

--

When locked is switched on from the tooltip's onclick (tap to pin), on a touch device the tooltip disappears right after the tap, locked stays true, and no further tap reaches onclick. The chart is stuck without a tooltip until it is remounted. With a mouse it works fine tho.

On touch, a tap dispatches pointerup → pointerleave → click. pointerleave calls hideTooltip(), which returns early only if locked is already true and otherwise schedules the clear:

hideTimeoutId = setTimeout(() => {
  if (!tooltipState.isHoveringTooltipArea && !tooltipState.isHoveringTooltipContent) {
    tooltipState.data = null;
    // ...

The click that follows sets locked = true, but the callback never re-checks locked, and the timeout is cleared only on the next show. So it clears tooltipState.data under the lock. After that every tap is ignored: showing is refused while locked, and the root onclick is only forwarded when tooltipState.data != null, so locked can't be set back to false.

Re-checking locked inside the timeout fixes it (checked against the repro above):

     hideTimeoutId = setTimeout(() => {
+      // The tooltip may have been locked since this hide was scheduled (e.g. tap to pin)
+      if (locked) return;
       if (!tooltipState.isHoveringTooltipArea && !tooltipState.isHoveringTooltipContent) {

Clearing hideTimeoutId when locked becomes true would work too.

For now I work around it by calling context.tooltip.show(e, data) in onclick right before locking, which cancels the pending hide.

layerchart 2.5.0 (same code on main at ddceba2), svelte 5.55.5, Chromium 147 (Playwright), touch emulation.

Will be happy to open a PR for it.

Thank you!