How to get buttons to span full height of window using Gtk.jl with Grid layout

I am trying to use the Grid layout (with Gtk.jl) but it is behaving differently to what I would expect. I expected that the grid would be set of cells which widgets can be inserted into the fixed cells and stretched in order to occupy the cell range defined. What I find is that the cell indices are taken to be relative to each other and that their position relative to each other is only important. Below is a MWE. How can I have a button, span the full height of the window? No matter how much of a range for the ‘y’ cells are put, it does not span those cells. @tobias.knopp

function welcomeWindow()
    welcome_Window_Main = GtkWindow("hi", 200, 400)    

    grid_Layout_Welcome_Window = GtkGrid()
    set_gtk_property!(grid_Layout_Welcome_Window, :column_homogeneous, true)
    set_gtk_property!(grid_Layout_Welcome_Window, :column_spacing, 10)
    A_button = GtkButton("Click Me A")
    grid_Layout_Welcome_Window[1:10,1:50] = A_button
    B_button = GtkButton("Click Me B")
    grid_Layout_Welcome_Window[20:90,1:10] = B_button
    C_button = GtkButton("Click Me C")
    grid_Layout_Welcome_Window[70:80,50:70] = C_button
    D_button = GtkButton("Click Me D")
    grid_Layout_Welcome_Window[80:90,70:300] = D_button
    E_button = GtkButton("Click Me E")
    grid_Layout_Welcome_Window[10:20,10:30] = E_button