Joe English - 2008-12-03

In the current implementation, the "field" element is responsible for both drawing the border and filling the background area with the window color (typically white). If you omit it, the border goes away (as desired) but the background will be filled with the frame color (typically gray) (not desired).

Either: [ttk::style configure Treeview -borderwidth 0] (not effective in all themes), or remove the field element from the layout and use [ttk::style configure Treeview -background $windowColor]. One or the other should work.