Hmm do you mean the text border where the icons used to be? Depends on the taskbar module, but look for something along the lines of xTaskbarFontLeftBorder or TaskbarButtonFontBorder. Something you may want to do, aswell, is look in the theme.rc and see which taskbar module is being loaded, and check out the readme file (\LiteStep\modules\docs or look in the right click menu). I'm not saying RTFM (atleast not in that way :D), but there you will find a lot of useful info (same for any module).