Here's the latest .NET head-scratcher: I wanted to put up an Open File dialog. Simple, use the OpenFileDialog class. Works great. Now I want to change the text of the Open button to "Insert". In the Win32 world, there's a hook procedure you can provide that lets you intercept window messages. You can customize the dialog by adding behaviors to specific messages. For example, on WM_INITDIALOG, you can change the text of a button.
Looking at the members of the .NET OpenFileDialog class, I see it has HookProc, described as:
Defines the common dialog box hook procedure that is overridden to add specific functionality to a common dialog box.
Perfect! Except that OpenFileDialog is a sealed class (C# lingo meaning you can't derive your own classes from it, like Java final). What?! How is this useful to me? D'oh! How do I override behavior in a common dialog?
And another thing: Why show me this member in the docs? Just as the docs don't describe private members, they should omit protected members in sealed classes.