Bug 145075

Summary:	Dynamically updating or injecting an iframe causes a textarea to lose its undo stack
Product:	WebKit	Reporter:	Pat O'Callaghan <patocallaghan>
Component:	HTML Editing	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	ap, enrica
Priority:	P2
Version:	528+ (Nightly build)
Hardware:	Unspecified
OS:	OS X 10.10

Description Pat O'Callaghan 2015-05-15 15:25:58 PDT

Yosemite 10.10.3
Safari 8

Steps to reproduce:

1. Type into the textarea
2. Dynamically inject an iframe or update the iframe's srcdoc using JavaScript
3. Focus the texarea and undo the last edit

What should happen:
The texarea should go back to the last edit.

What does happen:
The textarea loses its undo stack and doesn't change. This works fine on Chrome and Firefox. I haven't tested on IE.

Here's a JSBin which replicates the issue
http://jsbin.com/lodika/1/edit?html,js,output