Adding Child Forms to User Settings

It works for me (in Beta2), and works the same way regardless of whether the form is an mdiChild or not. In the Properties window for your control, e.g., a textbox, expand the (Application Settings) property. Click the ellipsis (...) button in the (PropertyBinding) field. This raises the Application Settings for 'textBox1' dialog. Scroll down to the property you want to bind, e.g., Text, and click the drop down arrow. You can choose one of your settings in the drop down, or define a new setting.

Don't forget you have to load and save the settings through code--settings don't persist between application settings automatically for you, e.g.:

Load:
this.textBox1.Text = Properties.Settings.Default.MySettingSetting;

Save:
Properties.Settings.Default.Save();