Pressing spacebar to toggle ToggleButton does not work

Steps to reproduce:
1. Compile & run:
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">
<fx:Declarations>
<!-- Place non-visual elements (e.g., services, value objects) here -->
</fx:Declarations>
<s:ToggleButton id="tb"/>
</s:Application>

2. Tab to the ToggleButton
3. Hit the spacebar

Actual Results:
Spacebar doesn't actually toggle the ToggleButton

Expected Results:
Spacebar should toggle the ToggleButton

Workaround (if any):