While VS2005 features a lot of tools and enhancements to boost your productivity, its bugs can sometimes just kill the time you saved using them. This one just took me some time to figure, although in the end, the resolution was universally trivial - restart the IDE.
Here's what happened: I tried to open my user control in the designer, and instead of visualizing the control, designer gave me the following message: "Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.", along with some pretty useless exception stack info. I haven't touched that control for a while so I was sure there's nothing wrong with it, and at runtime, it loaded and rendered without any problems. Cleaning and recompiling project didn't help. I was getting desperate and then tried the ultimate solution: I closed the IDE and reopened the solution. The problem went away.
[Update: there is a hotfix available for this one]
The other (known) bug I ran into the other day is with DataSet visualizer: fill DataTable with some records and delete one row. Open table with DataSet visualizer - deleted row doesn't render properly and accessing that row throws the "Deleted row information cannot be accessed through the row." exception.
The third one is related to the .suo file... I was working on my project while IDE suddenly crashed. No message, no nothing, the IDE just wasn't there anymore. Reopening the project resulted in a crash, before the project load was completed. Restarting computer didn't help. Deleting project's .suo file did... I didn't investigate this further, but I suspect it could be related to the fact, that I had *a lot* of code windows open while working on that project.
Oh, yes... and my toolbox window now looks like this (note the repeating icon):
There are a lot of other bug posts around the net, along with discussions, whether the VS2005 release was premature or not. I know MS VS team is working hard on these issues, but I would be more satisfied if MS started releasing monthly hotfixes, instead of waiting till summer for the first SP. [Update: Officially, Visual Studio 2005 Service Pack 1 will be released in Q3/2006]