Sizing
Explicit Sizing
Sizes can be declared explicitly in eto.
using Eto.Forms;
using Rhino.UI;
var parent = RhinoEtoApp.MainWindowForDocument(__rhino_doc__);
var dialog = new Dialog()
{
Width = 100,
Height = 100
};
dialog.Content = new Button() { Text = "Button" };
dialog.ShowModal(parent);
Declaring sizes forces Eto to use the sizes you give.

Implicit Sizing
If no sizes are declared, or if the sizes declared are -1
, Eto will auto-size controls, containers and windows.
using Eto.Forms;
using Rhino.UI;
var parent = RhinoEtoApp.MainWindowForDocument(__rhino_doc__);
var dialog = new Dialog();
dialog.Content = new Button() { Text = "I am a particularly wordy button, and I have a lot of information." };
dialog.ShowModal(parent);

Best Practices
// Minimum Sizes // Maximum Sizes? // Explicitly setting a size?