Please refer to the attached screenshot from the Demo application >> General Settings example. Workaround: private void radTreeView1_NodeFormatting(object sender, TreeNodeFormattingEventArgs e) { e.NodeElement.ExpanderElement.Margin = new Padding(2, 0, 0, 0); }
The item is duplicated with another issue in our Feedback Portal. You can track its progress, subscribe for status changes and add your comments on the following link - FIX. Themes - RadTreeView lines are not correctly displayed with most themes. ( https://feedback.telerik.com/Project/154/Feedback/Details/110731-fix-themes-radtreeview-lines-are-not-correctly-displayed-with-most-themes )