I suspect that most users would prefer to avoid calling technical support. Regardless of the company in question; this is simply not a fun way to spend your time. Adobe support is certainly no different.
The case was free; the aged adage "you get what you pay for" couldn’t be more glaringly obvious here.
The first gentleman that I spoke with clairvoyantly diagnosed my problem as corrupt files and insisted that there was no bug in Dreamweaver. As if intentionally trying to piss me off further, the support case was closed and marked "resolved." Bullshit.
But I decided to tighten up my own troubleshooting. I created a brand-new web site in Dreamweaver CS5 and used Fireworks CS5 to create a new single-pixel PNG with transparency enabled. Of course, as with the files from this blog site, Dreamweaver’s Design Mode rendering chewed up kernel mode time. The moment that the PNG background was removed, kernel mode time barely showed up in my Performance Monitor traces.
I called back and created a new free support ticket. This time, the support engineer spent a couple of hours on the phone with me. I let him record my desktop so that everything we did would be documented. We reproduced the kernel mode time spikes at least a dozen times. We created a new background graphic in JPG format – this does not support transparency and thus does not give me the visual effect I wanted – it also did not spike kernel mode time. The engineer then asked for research time; which I gladly granted.
Progress! An illusion that I was quickly disabused of when he called me back. "I cannot reproduce the problem here. Please upload your files so I can escalate this issue."
After the upload, the case went dead for nearly two weeks. Then I was called back by a new engineer. Clearly, the case had not yet been escalated because this time I was told that JPG and GIF are the standard image types that all web developers use.
This really angered me. Adobe Fireworks uses the PNG format natively! After arguing this point, she agreed to keep working on this issue. We recorded another movie of my desktop reproducing the problem repeatedly. We even downloaded the trial software for Dreamweaver CS5 just to test a different set of program files. What a waste of my time!
I generated a user mode dump of the Dreamweaver process from the Task Manager (a nice feature in Windows 7) and uploaded that to Adobe.
It has been 7 days since I last asked for an update (the Adobe support page promises follow-up in 24 hours).