Describe the bug
If you select a message in the message list in the Junk folder, you cannot scroll the list whereby the selected message is outside of the viewport.

Reproduction steps

• Enable spam scores extension
• Go to the Junk folder
• Click on a message
• Try to use the scroll bar or mouse wheel
• You cannot scroll, the viewport "rubberbands" back to having the selected message shown

Expected behavior
Normal behavior is that selected message scrolls outside of the viewport and a "shadow" cursor follows the mouse. This is what happens when the plugin is disabled.

Screenshots
A screenshot wouldn't be helpful, the problem is only demonstrable interactively.

Thunderbird (please complete the following information):

• OS: Fedora 34
• Version: 102.1.2 (64-bit)
• Package directly downloaded from Mozilla

Spam Score add-on (please complete the following information):

• Version: 1.4.1

Additional context
Plugin works fine otherwise, the only issue I notice is the scrolling issue. Problem abates when disabling the plugin.