Custom Role Unable to See Commission Transactions under Transactions Subtab on Entity Record

Steps to reproduce the problem:

1. Login using Custom Role.
2. Navigate to Lists > Relationships > Vendors.
3. Click View on a Vendor Record.
4. Navigate to Financial tab> Transactions subtab.

Actual Result: Custom role is unable to see all Commission transactions.

The user confirmed that the filters on the Transactions sublist has Type= All and View= Default.

To resolve this, as an Administrator, perform the following:
1. Navigate to Setup > Users/Roles > Manage Roles.
2. Click Edit on Custom role
3. Uncheck Sales Role box.
4. Click Save.

Note: Per Field Level Help: 

Checking this box does the following:

If you set restrictions in the Employee Restrictions field, check this box if employees using this role should be restricted based on the Sales Rep field on records and transactions.

Users with this role can only see quota, forecast, and commission data for themselves and their subordinates.