Updating Source causes star-sized columns to collapse

[SuperJMN]

I was trying to overcome this issue. To do so, I set a new Source every time the model changes, in order to force the TreeDataGrid to update its contents.

However, this has led me to another bug:

• When TreeDataGrid.Source is set the 1st time, things go OK
• but when you try set it afterwards, star-sized columns collapse.

TreeDataGridWeirdColumn_JmNitN6nAj.mp4

The code to reproduce this is really simple. You can reproduce it by cloning this repo

TreeDataGrid version: 0.10.10

[FrayxRulez]

This should be relatively easy to address, as a workaround we're doing this right after setting the Source:

void layoutUpdated(object? sender, EventArgs e)
{
    Tree.LayoutUpdated -= layoutUpdated;

    var c = Tree.RowsPresenter?.GetVisualParent();
    if (c != null)
    {
        Tree.RowsPresenter?.Columns?.ViewportChanged(new Rect(0, 0, c.Bounds.Width, c.Bounds.Height));
    }
}

Tree.LayoutUpdated += layoutUpdated;