Summary

• Add pressedArrow property to TreeView, following the same pattern as pressedCtrl and pressedShift
• Allows consumers to distinguish arrow key navigation from mouse click selection in select/deselect event handlers

Motivation

The PlayCanvas Editor's Assets panel has a folder TreeView where clicking a folder once navigates into it, and clicking it again shows it in the Inspector. When using arrow keys to navigate between folders, the Inspector should update — but the select event provides no way to distinguish keyboard navigation from mouse clicks.

This adds the missing piece: pressedArrow is true during select/deselect events triggered by arrow key navigation in _onChildKeyDown, and false otherwise.

API

treeView.on('select', (item) => {
    if (treeView.pressedArrow) {
        // selection was triggered by arrow key navigation
    }
});

Test plan

• Verify pressedArrow is true inside select/deselect handlers during arrow key navigation
• Verify pressedArrow is false inside select/deselect handlers during mouse clicks
• Verify pressedCtrl and pressedShift behavior is unchanged