Put your cursor on the part of the expression that you want to debug and press F9 to set a breakpoint. Setting breakpoints by clicking in the gutter doesn't work for LINQ like you might expect - you have to use the hotkey.
I frequently hear complaints about debugging LINQ, but Visual Studio supports it well enough. Microsoft could have done a better job informing people about it.
I frequently hear complaints about debugging LINQ, but Visual Studio supports it well enough. Microsoft could have done a better job informing people about it.