Control Resizing on a UserControl in WinForms

Let's say you have a UserControl, and on that user control, you have placed a control (any control), setting the Dock property to Fill. From hereon, we will refer to this control as the "filling control".

Let's further assume that you've placed a Panel (or other type of appropriate container) onto a Form, and set the Anchor property of the container to grow/shrink when you resize the form.

Finally, you would probably programatically add the user control (that contains the filling control) to the panel.

If you perform the steps outlined above, you will observe that the filling control will NOT resize itself to the container control, even though the container control will happily obey the Anchor property setting.

The problem is that the designer doesn't allow you to set either the Dock or the Anchor properties. You MUST manually set the appropriate property in the UserControl Load event handler (or someplace else equally appropriate).

I struggled with this for two hours (trying to capture Size events, and other things) before stumbling on the solution. I had completely missed the fact that there were no Dock/Anchor property settings in the designer for UserControl objects.