PDOMTree cannot change focus while scenery is already responding to a…

… focus change, see phetsims/density-buoyancy-common#382
phetsims · Sep 6, 2024 · 9722647 · 9722647
1 parent 44e2c80
commit 9722647
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Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/js/accessibility/pdom/PDOMTree.js b/js/accessibility/pdom/PDOMTree.js
@@ -402,7 +402,11 @@ const PDOMTree = {
    * @private
    */
   afterOp( focusedNode ) {
-    focusedNode && focusedNode.focusable && focusedNode.focus();
+
+    // If Scenery is in the middle of dispatching focus events, it is buggy to change focus again internally.
+    if ( !BrowserEvents.dispatchingFocusEvents ) {
+      focusedNode && focusedNode.focusable && focusedNode.focus();
+    }
     BrowserEvents.blockFocusCallbacks = false;
   },
 

diff --git a/js/input/BrowserEvents.js b/js/input/BrowserEvents.js
@@ -23,6 +23,10 @@ const BrowserEvents = {
   // caused by user interaction.
   blockFocusCallbacks: false,
 
+  // True while Scenery is dispatching focus and blur related events. Scenery (PDOMTree) needs to restore focus
+  // after operations, but that can be very buggy while focus events are already being handled.
+  dispatchingFocusEvents: false,
+
   /**
    * Adds a Display to the list of displays that will be notified of input events.
    * @public
@@ -763,12 +767,16 @@ const BrowserEvents = {
 
     // NOTE: Will be called without a proper 'this' reference. Do NOT rely on it here.
 
+    BrowserEvents.dispatchingFocusEvents = true;
+
     // Update state related to focus immediately and allowing for reentrancy for focus state
     // that must match the browser's focus state.
     FocusManager.updatePDOMFocusFromEvent( BrowserEvents.attachedDisplays, domEvent, true );
 
     BrowserEvents.batchWindowEvent( new EventContext( domEvent ), BatchedDOMEventType.ALT_TYPE, 'focusIn', true );
 
+    BrowserEvents.dispatchingFocusEvents = false;
+
     sceneryLog && sceneryLog.OnInput && sceneryLog.pop();
   },
 
@@ -778,12 +786,15 @@ const BrowserEvents = {
 
     // NOTE: Will be called without a proper 'this' reference. Do NOT rely on it here.
 
+    BrowserEvents.dispatchingFocusEvents = true;
+
     // Update state related to focus immediately and allowing for reentrancy for focus state
-    // that must match the browser's focus state.
     FocusManager.updatePDOMFocusFromEvent( BrowserEvents.attachedDisplays, domEvent, false );
 
     BrowserEvents.batchWindowEvent( new EventContext( domEvent ), BatchedDOMEventType.ALT_TYPE, 'focusOut', true );
 
+    BrowserEvents.dispatchingFocusEvents = false;
+
     sceneryLog && sceneryLog.OnInput && sceneryLog.pop();
   },