Update May 11th, 2021:
Microsoft has released an update that fixes this. Run through Windows updates to get to version 18363.1556 (Windows KB5003169)
A recent Windows update caused the scroll bars in Thunder to vanish.
This only affects customers running Windows 10 1909 (18363.1500). To check the version you have installed go to Start > Run, and type in winver and hit enter. If you have the version listed above, perform the below steps.
- Click on Start and select Settings
- In Settings go to Update & Security and then View Update History.
- Click on Uninstall updates.
- Look for "Security Update for Microsoft Windows (KB5001337)"
- Alternatively, if "Security Update for Microsoft Windows (KB5000850)" is installed, that will need to be removed as well.
- Right click and Uninstall this update.
Once this updated is removed, you may be asked to restart. The next time you run Thunder, the scroll bars will be back.
If you have Football 188.8.131.52, Hockey 184.108.40.206, or Thunder Baseball you may also choose to update to Windows 10 2004 or 20H2 to bypass the issue as well.
This is a listed known issue from Microsoft: