To add to Charles comments about the 'why' a feature is needed - I used to work for a large communications company and we would regularly raise feature enhancement requests, on behalf of our customers, with our developers. Saying "We would like this" and not providing a use case (the why and how) for the feature would most of the time end up with a feature (if implemented) that wouldn't meet a customer's requirements at all. In addition, there was also an assumption sometimes that "oh, someone else has already requested it so I won't bother requesting it too"....this would also result in the use case being missed too. I remember clearly one of our biggest customers requesting something and not providing much detail on the why and how - the feature was put in, and then the same customer came back and said that it didn't meet their requirements and they wanted this and that added to it......the final functionality eventually made it in, but it could have been so much quicker if the why and how was provided in detail at initial request time.
Is this for private messages? If so, I'm pretty sure that the ability to check those hasn't ever been a feature at all, and the functionality has been provided by an application/hook/plugin previously, such as this:
And here is the result: The displayed embedded content is in an iframe.The URL to the content is http://community.invisionpower.com/topic/416215-408/?do=embed&embedDo=getNewCommentFeel free to click that to see what exactly is loaded in the embedded content.
Let's test it then - please pick a topic, any topic, and paste the link and allow it to embed (I'll let you choose). Then it can be checked quite easily in the DOM (I'll let me do that, if you don't want to)
Nope - as soon as the Submit button is clicked it turns to 'Saving' button so that rules that one out. Other possible causes: a perceived delay in the person's submission, they get bored and refresh the page and then they see some auto-saved data in the post box and they press Submit again. Result: a double post.
Thing is though - the editor itself does work, and works quite well. That quote functionality, however, is provided by the IPS plugin 'ipsquote' and that is where these problems lie. You're doing a great job here of documenting these bugs, but have they been entered into the bug tracker for reference? Get them thrown in there if not. As a test - could you see if you can reproduce these issues at all using the standard CKEditor 'Block Quote' plugin? http://ckeditor.com/demo#full
When you open it up, look to the left and notice what is highlighted - and then go ahead and click on the various sections (I've got no 'profile comments' at this time, so "There is nothing here yet" is correct)