FIX. RadRichTextEditor - all dialogs opened through the RichTextEditorRibbonBar should not be resizabe
Workaround: set the FormBorderStyle property to FixedSingle for the respective dialog.
RadForm f = this.radRichTextEditor1.RichTextBoxElement.FontPropertiesDialog as RadForm;
f.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;