When I insert a youtube iframe code my html editor is freezing and it takes a while before its normal again.
Also the "External Preview" doesn't display the site anymore and with every change I make it freezes until I remove the youtube iframe code.

I had that also on a different computer at work. The only thing is that I thought it was that computer because the server has very strict rules so installing a program on those computers often don't work well.

I don't have that problem with other iframe codes but with youtube so far.

A lot of scripts that pull elements from other resources have that problem. (Ever tried a Google map?) This is not a fault in the software but depends on the distance and routing that those pulled elements have to pass before they show up on your computer screen.
I'm in Turkey at the moment, and here it takes 'ages' for the CoffeeCup site to open, but when I'm home in Norway, it opens in a snap. I have recently inserted a Facebook script into a site, and that also froze up my preview. Inserting the same script from home is no problem.
That's just the way it is.

No it's not because I just have this problem with the youtube script and the coffeecup editor is freezing.
The software shouldn't freeze.

Also I have a google maps script which loads instantly and a contact form which is an iframe from another site which is also loading instant.

I have a gaming pc and a 200 Megabit fiber internet connection so it shouldn't cause problems.

Here is a video https://docs.google.com/file/d/0B43zIdqNkx5rUHZkYm5IMmU5LWM/edit?usp=sharing&pli=1
Put it on full hd!

Add this to the iframe script src.
http:

Oh nice that works
I didn't even saw that there was just standing // instead of http://.

Thanks for replying and helping me out!

Your welcome.

Yep, crashes for me with the youtube iframe. Every time.....Any answers out there?

The best thing to do for this type of issue is to make sure your scripts are correct and linking is correct. If that doesn't do it open a support topic.