Font Sizes
You can repopulate the Font Size dropdown with the sizes from 1 to 7 (these are the browser supported values). You can set the FontSizes collection declaratively, programmatically and using the ToolsFile.
Adding to FontSizes Collection Declaratively
<telerik:RadEditor RenderMode="Lightweight" runat="server" ID="RadEditor1">
<FontSizes>
<telerik:EditorFontSize Value="1" />
<telerik:EditorFontSize Value="3" />
<telerik:EditorFontSize Value="5" />
</FontSizes>
</telerik:RadEditor>
Adding to FontSizes Collection Programmatically
Use the FontSizes collection Add() method to include new FontSizes in the list.
RadEditor1.FontSizes.Add("1");
RadEditor1.FontSizes.Add("3");
RadEditor1.FontSizes.Add("5");
RadEditor1.FontSizes.Add("1")
RadEditor1.FontSizes.Add("3")
RadEditor1.FontSizes.Add("5")
Using ToolsFile.xml
You can also populate the FontSizes dropdown using the ToolsFile, as shown in the example below:
<root>
<tools name="MainToolbar" enabled="true">
<tool name="FontSize" />
</tools>
<fontSizes>
<item>1</item>
<item>3</item>
<item>5</item>
</fontSizes>
</root>
If you want to apply font sizes in pixels (px) or in points (pt) then use the Real Font Size dropdown.