Update **** April 26/07 See End of Article.
This product ultimately received 3 Stars
for the reasons you will see upon reading further...
This is so ironic that I'm writing a review about FCK Editor for the DotNetNuke Platform, and while I type within the FCK editor, I fear pressing update because it has been resulting in Poof! All the text disappearing!
Don't get me wrong, I love the power of the FCK Editor. It's hard to go back to the FreeTextBox editor that comes installed as the default WSIWYG editor on DNN. But! I've been experiencing strange anomalies using this add-on and I've found no mention on the net about it. I went to their site and they want me to pay $175.00 US for one year of email support. Phuff! (wait, I'm going to CTRL+A and CTRL+C my text before I hit update)... Whew! It worked this time.
The fact that I'm having problems with DNN is not new. Every time I try something different that didn't come with the default install of DNN, there are "issues." I've reinstalled the platform many times now because of something either I've done, or the module has done, and has rendered the site "Nuked!" But I'm tired of starting from scratch every time something goes wrong so this is the reason for the reviews I've started to do.
OK, lets start with what I do know. I've just did a fresh install of DNN 4.4.1 on my hosting provider www.webhost4life.com (I'll have a review on them later on as well.) (Back Track! I went to attach a screen shot for this entry and lost everything)(Poof! #1)
Now what was I saying. I had a bunch of other stuff written here now and I've forgotten after all that. Oh ya! I was explaining how I did a fresh install and was pretty sure that I don't have any conflicting software but, now I'm not so sure. I've been having weird things happening to the Blog Module and haven't done anything else to the site other than when I do a fresh install of DNN, I now turn on the new "Compression settings" and "Whitespace filter" and I follow some of the recommendations found on the ASP.NET forum titled "Optimizing DNN for speed - Please contribute". I set "Page Persistence" to "Memory", I choose the "Scheduling Method" of "Timer Method" and, finally I do the normal email settings, mail host and site title/description etc;. (CTRL+C) Update!
I'm thinking there might be something wrong with the new compression and performance settings on this DNN 4.4.1 install so I'll turn it off and try that. (CTRL+C) Update!
Some Success!
I think I found some of the problem. Earlier, I had tried to attach a screen shot and lost half of what I typed in. Another weird thing that was happening was on this blog module, you choose which parent blog you want to post this article to. Well, it was miss behaving because sometimes when I went to update the page, I would get a validation error on the parent blog selector saying "Entry Required" and the selector for the entry was blank and indeed, I had selected the parent blog before proceeding. After turning off the Compression and Whitespace filter under the host settings for the portal, it seems to have stopped misbehaving for now.
I can verify that the Free Text Box editor does not do this because I only started to have disappearing text after starting to use FCK editor. I always turn on maximum compression and whitespace filter because I like the performance increase and response it gives to the site and never experienced this disappearing text problem before.
Here's an error I got while trying to change the screen shot pictured below for a higher resolution. After capturing this error, I copied the text and pressed the back button on my browser. I retried and Success Again! We'll call this (Poof! #1.5) because I didn't technically loose anything that time.

Final review for FCK Editor. 3 stars 
Pro's: I like the advanced features, such as the ability to right click and adjust image properties and links or control tables visually rather than playing with the .html. I also really like the full screen view.
Con's: I don't like the fact that this module conflicts with DNN's new compression and/or Whitespace filter settings. I also don't like that there are less Style and Format selections from the drop down selectors on a default install. Now I have to go figure out how to get back more of the styles I had with the default Free Text Box editor. I might have to read the documentation further. I didn't have to do that by default. It just worked. I guess having more features requires more reading?
Overall/Comments: I would think that there would be a forum of some kind from their site where I could post my comments in the hopes of administration reading it. I get the impression that this is a very popular editor and wonder why there isn't a forum? (CTRL+A and CTRL C) Update. Just in case. 
Update: March 25, 2007
I continued to experience text loss so I went through a more systematic approach to explore just exactly which setting is conflicting. I started by selectively turning off settings from how I usually set up the host site, back to the way it comes before I change anything. Here's what I found;
- Compression amount turned down to "GZIP" 5 from 9 - Poof!
True!
- Compression changed for the type "GZIP" to "Deflate" 5 - Poof!
= True!
- Compression OFF - Poof!
= True! (surprisingly)
- Whitespace filter OFF - Poof!
= True!
- Page Persistence selection "Memory or Page" selected - Page (default) - Poof! = False!

Wow! that was surprising! I thought it was the compression settings that were conflicting but it turns out that you need to have "Page State" set to "Page" instead of "Memory." When set to "Memory," you won't see all that gargon code at the bottom of your page source view and this can apparently have a performance increase. Well so much for performance! This site is less responsive now but I make up time by not loosing my work. I'll have to keep bugging my web host for more performance!
As far as reporting this bug. Well, FCK editor will have to pay me $175.00 US/year to provide email support for that.