title: GTK+ alignment and resizing with Glade
body: <p>I am prototyping an application interface in Glade (GTK# 3.20 + C#) and use my CSS styles via CssProvider. I have this:</p>
  
  <p><a href="https://i.stack.imgur.com/sgoD9.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sgoD9.png" alt="enter image description here"></a></p>
  
  <p>The problem is that I am using GTKLayout as my main container and I think it's the wrong way to create the UI. I am using this type of container because it give me the ability to resize and drag widgets as I want within the Glade during the prototyping. The bad thing is that widgets stuck at left top corner of the application window when I am resizing it. I made a min size for the window, but I want the UI to be adaptive when the window size is increasing. You can see the problem below:</p>
  
  <p><a href="https://i.stack.imgur.com/A6IKF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/A6IKF.png" alt="enter image description here"></a></p>
  
  <p>I tried to create this UI with Box container, Grid container and so on. But I always had the same problem: the size of all the widgets was fixed (in Glade during the prototyping) and it looked like it was impossible to create the complex UI with it.</p>
  
  <p>So, I want some experienced people to explain me a few things:</p>
  
  <ol>
  <li>If I am using GTKLayout in a wrong way how should I organize my widgets (in which containers) to have the ability to resize them like I want (In Glade) and to have the same look like at my screenshot.</li>
  <li>If it's not a bad practice to use GTKLayout, how should I solve the alignment problem to make an adaptive UI?</li>
  <li>If it's a bad practice to use GTKLayout, how should I make an adaptive UI and with which containers?</li>
  </ol>
  
  <p>Here is the structure of the window (yes, I am using Label widget to create color panels):</p>
  
  <p><a href="https://i.stack.imgur.com/rseUc.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rseUc.png" alt="enter image description here"></a></p>