Currently, there are only three ways to pause the ticker from scrolling.
1.) You can simply hover your mouse over the ticker. This will pause the scrolling until you move your mouse away.
2.) You can right click (left click + ctrl) on the ticker and select "Stop Scrolling". This will stop the ticker from scrolling until the next time the app starts up or you right click on the ticker and select "Start Scrolling".
3.) If you only have 1 stock in your watch list, the ticker will not scroll.