To reproduce: - Create a new form. - Change the Localizable property to true. - Add a RadLabel to the form. - Select the label and change its name to "name with space" and press Enter. - VS editor will say that it is an invalid name and return the name to previous value. - Now look at designer.cs file of the form and you will see a lot of RootElement properties getting values form resource! Same issue can be reproduced by localizing a custom control: - Open UserControl.cs in Design mode. - On property editor, change property Language from "(Default)" to "Portuguese (Brazil)". - Now change a label text to "Nome". - See file EditUserControl.Designer.cs. It has many RootElement lines! Workaround: Delete the generated code and rebuild.