After looking at the CRM demo I decided to implement a similar type of functionality where based on a bool state the grid would show either a few columns or all columns
<telerik:RadGridView helpers:GridViewColumnHelper.HideNonImportantColumns="{Binding IsInOverviewState}"
ItemsSource="{Binding Contacts}" ColumnWidth="*"
I am using Prism, everything works fine if I set a Minimum Height and Width of the main Shell and set the WindowState to normal. However, if I start the application maximized without these settings, when the grid is loaded, although it shows the right number of columns the width of the grid is incorrect (too big), if I slightly adjust the size of the window everything sorts itself out.
This is the grid definition
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="2*"/>
<ColumnDefinition Width="2*"/>
</Grid.ColumnDefinitions>
if you see the attached files you will see what I mean.
Thanks for any help in advance.