Run first setState with explicit priority in case of non-React event handlers

src/devtools/views/Components/TreeContext.js

@@ -27,7 +27,11 @@ import React, {
   useReducer,
   useRef,
 } from 'react';
-import { unstable_next as next } from 'scheduler';
+import {
+  unstable_next as next,
+  unstable_runWithPriority as runWithPriority,
+  unstable_UserBlockingPriority as UserBlockingPriority,
+} from 'scheduler';
 import { createRegExp } from '../utils';
 import { BridgeContext, StoreContext } from '../context';
 import Store from '../../store';
@@ -699,7 +703,10 @@ function TreeContextController({ children }: Props) {
 
   const dispatchWrapper = useCallback(
     (action: Action) => {
-      dispatch(action);
+      // Run the first update at "user-blocking" priority in case dispatch is called from a non-React event.
+      // In this case, the current (and "next") priorities would both be "normal",
+      // and suspense would potentially block both updates.
+      runWithPriority(UserBlockingPriority, () => dispatch(action));
       next(() => dispatch({ type: 'UPDATE_INSPECTED_ELEMENT_ID' }));
     },
     [dispatch]