You can view a diff on a single file over multiple commits in the Log/History tab of source tree.  

However I am not able to do this in the Search tab.  This functionality really needs to be extended to the Search tab, as we put the ticket number in our commit message and when looking up code from an old ticket you want to search for all commits with the ticket number in the message.  You can do this on the search tab, but not get the consolidated diff that you can on the Log/History tab.

Another thing is that the consolidated diff that you can get through the Log/History tab is only from one commit to another.  Eg; it includes all the commits in between.  You can't just say show me this one and that one together.

All these things are an essential part of our workflow and could be done in SVN.  Now we have moved to git/SourceTree, how do we do these things?

Can the above functionality please be implemented in SourceTree, I think it would really add value to the product.