In some of my grids I am having issue with the headers not fully loading correctly until after the ItemsSource is loaded for the first time. My grid will display with some of the headers being cut off, and then when the data finishes loading from the server, the headers will correctly finish rendering.
I believe it may be an issue when mixing column headers where some columns have a set width and others rely on ColumnSizer.Star.
Attached is an example of this issue occurring. It is easier to see the issue on the iPad, although it also appears on the iPhone in landscape. You will be presented with a button. When pressed, the grid should display with part of the last header not displaying correctly. After 2 seconds, the data will load and the headers will size correctly.