On version 3.0.8 P4Merge Diff Tool doesn't start.
- Open Source Tree.
- Click on any commit.
- Click on any text file changed in the commit.
P4Merge is started and file changes are presented.
HOWEVER when I open Tools/Options/Diff and click OK without making any changes, Ctrl+D works fine until next SourceTree restart.
UPDATE: I don't have to open Diff tab. Clicking Tools/Options/OK also "activates" P4Merge.
Below my Diff settings: