After applying another skin to get taskbar back to one row then reapplying your skin it applied as for you, as double.
I have played with settings for text margins and font size for buttons and sys tray, was able to get sys tray icons back to one row but taskbar size will not change, in fact the buttons just get smaller height wise on taskbar.
Maybe Vstyler or someone else will see thread and be able to help.
Maybe, if you have updated to latest WB version as I have, you have found a new WB bug.