Deleting a single Submodule in SourceTree results in the deletion of all submodules in this repo

Summary

If a repo in SourceTree has multiple submodules, deleting one of them will result in the deletion of all submodules.

Environment

SourceTree for Windows, version 1.7

Steps to Reproduce

1. Open the tab of a git repo in SourceTree
2. Add two submodules
3. Right click on one of the submodules, named e.g. X, and select Delete X

Expected Results

Submodule X is deleted from the repo.

Actual Results

Both submodules in this repository are removed.

Workaround

No workaround available.