I'm making a tests with customizing the appearance - I noticed, that changing background colour of treewidget, for example: ttk::style configure Row -background lightblue ...changes only the background colour of the lines, which have any data entries. If the treewidget's window is bigger than needed - that empty area remains white. I think, it's a bug; the entire area should have new background colour, not just used rows. Or perhaps I missed other option? -- ZB