Until last week my Taskbar was, as it has always been, one line deep, in other words the same depth as the Start icon on the extreme left.
Suddenly the Taskbar became three lines deep, as shown below.
(I have only shown the right hand side, the left is similar)
I have no recollection of doing anything which might have caused it to change this way.
Help says unlock the taskbar, take hold of the top sizing bar, and move it to the size required.
The problem is that I can move the sizing bar up thus increasing the depth, which makes it worse, but I cannot move it down without the whole taskbar moving off the screen at the bottom.
How can I return it to the way it used to be, one line deep ?