Right click and uncheck 'Lock the Taskbar' if it is checked.
Next use the mouse to grab the edge to the Taskbar a drag it down to a
single width.
Lock the Taskbar.
Drag the divider on the bottom line, just to the right of the "Start"
button, up and to the right of the QL bar on the top line. When you
release, you should be able to resize the height of the Taskbar.