In custom cabinets, there are several methods to modify the material of the top line/foot line:

Method 1, Select the cabinet/door panel, and then click the format brush - material brush in the upper bar, and brush it onto the corresponding top line/foot line;

Method 2, Right-click on the top line/foot line - Material - Line Material, and enter to select the material you want;

Method 3, Right-click on the top line/foot line - Line Editing, click on the material thumbnail in the section and material of the right line editing bar to re-select the material you want, and confirm.