When I work on WPF projects I like very much the Snoop application. It allows me to debug visual tree of WPF app and look into what properties of controls are having what values in real time – to see what can be done to improve layout (like fixing margins etc.), what data bindings and data contexts are currently used and many other things. If you did not try Snoop – just try it – it is free and very useful.
When working in Silverlight I always wanted we have this kind of tool for Silverlight too – and I found it!
Silverlight Spy – is what I was looking for. The best thing about this app – is – it has Free Edition available. The licensing page on developer’s website says free edition is limited – but after evaluating free version few minutes I am pretty satisfied with what it provides.
I advice you to try it and I am sure you will find it useful!