A customer recently asked Developer support for guidance on how to remove (collapse) the restore button in a tile that has been maximized.  The following Style can be added to the controls Resources in XAML to accomp[lish this:

<igTiles:XamTilesControl.Resources>

                <Style TargetType="{x:Type igTiles:Tile}" >

                    <Style.Triggers>

                        <DataTrigger Binding="{Binding State, RelativeSource={RelativeSource Mode=Self}}" Value="Maximized" >

                            <Setter Property="MaximizeButtonVisibility" Value="Collapsed" />

                        </DataTrigger>

                    </Style.Triggers>

                </Style>

           </igTiles:XamTilesControl.Resources>