External Merge Fails to Launch When Remote File is Deleted and Local Changed

Steps to reproduce:

1. Configure Beyond Compare as merge and diff tool.
2. Confirm that the 'external diff' successfully launches Beyond Compare via any Git repository.
3. Create a new local Git repository.
4. Add several commits.
5. Cause a fork, and conflict:
   1. Developer A deletes a file.
   2. Developer B edits the file.
6. Developer A pushes.
7. Developer B pulls (with rebase checkbox selected).
8. Rebase is halted due to the conflict.
9. Developer B attempts to resolve conflict, by Right Click > Launch External Merge

Expected behaviour:

• A message that the remote file was deleted
• Launch of Beyond Compare, with 'remote' being an empty file.

Actual behaviour:

• Beyond Compare never launches and the merge dialogue remains open.