The mouse cursor cannot be used to drag the scroll bar within the chat UI

The Bug:

The mouse cursor cannot be used to drag the scroll bar within the chat UI.

Steps to Reproduce:

• Type lots of messages in chat so that the scroll bar appears within the chat UI.
• Open the chat UI and hover your mouse cursor over the chat scroll bar.
• Begin holding the chat scroll bar and attempt to navigate chat by dragging it.
• Take note as to whether or not the mouse cursor can be used to drag the scroll bar within the chat UI.

Observed Behavior:

The mouse cursor cannot be used to drag the scroll bar within the chat UI.

Expected Behavior:

The mouse cursor would be able to be used to drag the scroll bar within the chat UI, just like how other scroll bars work within other menus.