Block insertion in table caption

[garry.yao]

1. Load the following content:

   <table border="1" cellpadding="1" cellspacing="1" >
   					<caption>table caption</caption>
   					<tbody><tr><td>cell</td></tr></tbody>
   				</table>
   

2. Click inside the table caption and insert a horizontal line;
   • Actual Result: JavaScript error thrown.
   • Expected Result: block insertion should be disabled at the cursor position

[garry.yao]

Same issue applies to the legend tag:

<form>
	<fieldset>
		<legend>fieldset^ legend</legend>
		height: <input type="text"/>
		weight: <input type="text"/>
	</fieldset>
</form>

[Reinmar]

Block elements can be now inserted into the table caption without a problem, because caption in HTML5 allows ​flow elements. However, legend element does not allow flow elements, but only phrasing, therefore insertion isn't possible.