Hi,
In Sourcetree, I've selected DiffMerge as my external diff and merge tool, and when I select a file with conflicts I can launch it to compare diffs using "Actions/External Diff". But I cannot launch it to perform merges using "Actions/Resolve Conflicts/Launch External Merge Tool", as this menu option is greyed out. (In fact, all of the option in "Resolve Conflicts" are greyed out entirely. Any suggestions?