Fix rare crash in event handler (#7525)

* fix that addEventListenerWithDelegation could crash on non-Element event targets

* update changelog

CHANGELOG.unreleased.md

@@ -38,6 +38,7 @@ For upgrade instructions, please check the [migration guide](MIGRATIONS.released
 - Fixed a bug where meshes (or chunks of them) were always colored white, if they were loaded while the corresponding segmentation layer was disabled. [#7507](https://github.com/scalableminds/webknossos/pull/7507)
 - Fixed a race condition when opening a short link, that would sometimes lead to an error toast. [#7507](https://github.com/scalableminds/webknossos/pull/7507)
 - Fixed that the Segment Statistics feature was not available in the context menu of segment groups and in the context menu of the data viewports. [#7510](https://github.com/scalableminds/webknossos/pull/7510)
+- Fixed rare bug which produced a benign error toast on some mouse interactions. [#7525](https://github.com/scalableminds/webknossos/pull/7525)
 - Fixed a bug where dataset managers were not allowed to assign teams to new datasets that they are only member of. This already worked while editing the dataset later, but not during upload. [#7518](https://github.com/scalableminds/webknossos/pull/7518)
 - Fixed regression in proofreading tool when automatic mesh loading was disabled and a merge/split operation was performed. [#7534](https://github.com/scalableminds/webknossos/pull/7534)
 - Fixed that last dimension value in ND dataset was not loaded. [#7535](https://github.com/scalableminds/webknossos/pull/7535)

frontend/javascripts/libs/utils.ts

@@ -765,10 +765,12 @@ export function addEventListenerWithDelegation(
   handlerFunc: (...args: Array<any>) => any,
   options: Record<string, any> = {},
 ) {
-  const wrapperFunc = function (event: Event) {
-    // @ts-ignore
-    for (let { target } = event; target && target !== this; target = target.parentNode) {
-      // @ts-ignore
+  const wrapperFunc = function (this: HTMLElement | Document, event: Event) {
+    for (
+      let { target } = event;
+      target && target !== this && target instanceof Element;
+      target = target.parentNode
+    ) {
       if (target.matches(delegateSelector)) {
         handlerFunc.call(target, event);
         break;