Today I ran into a breaking change in .NET 4 which I couldn't find in the documentation. It's about binding a linq to objects query to a BindingSource's DataSource in winforms. The code works properly in .NET 3.5, but crashes in .NET 4:
Once in a while we get requests about how to fix performance problems with our framework. As it comes down to following the same steps and looking into the same things every single time, I decided to write a blogpost about it instead, so more people can learn from this and solve performance problems in their O/R mapper powered applications. In some parts it's focused on LLBLGen Pro but it's also usable for other O/R mapping frameworks, as the vast majority of performance problems in O/R mapper powered applications are not specific for a certain O/R mapper framework.