Just an update. This seems to be an issue only with the latest version of IE 10. A co-worker has an older version of IE 10 and the toolbar looks fine (just like in Firefox).
Here's one of the control definitions:
<
telerik:RadEditor
ID
=
"reEnvironment"
runat
=
"server"
EditModes
=
"Design"
ContentAreaMode
=
"Div"
NewLineMode
=
"P"
ToolsFile
=
"~/App_Data/RadEditor/Tools.xml"
ToolbarMode
=
"Default"
AutoResizeHeight
=
"true"
Height
=
"100px"
Width
=
"100%"
Content='<%# Bind("Environment") %>'
OnClientLoad="RadEditorOnClientLoad">
</
telerik:RadEditor
>
<?xml version="1.0" encoding="utf-8" ?>
<root>
<modules>
<module name="RadEditorHtmlInspector" enabled="false" visible="false" dockingzone="bottom" />
<module name="RadEditorNodeInspector" enabled="false" visible="false" dockingzone="bottom" />
<module name="RadEditorDomInspector" enabled="false" visible="false" dockingzone="bottom" />
<module name="RadEditorStatistics" enabled="false" visible="false" dockingzone="bottom" />
</modules>
<tools>
<tool name="Bold" shortcut="CTRL+B"/>
<tool name="Italic" shortcut="CTRL+I"/>
<tool name="Underline" shortcut="CTRL+U"/>
<tool separator="true"/>
<tool name="ForeColor"/>
<tool name="BackColor"/>
<tool separator="true"/>
<tool name="JustifyLeft"/>
<tool name="JustifyCenter"/>
<tool name="JustifyRight"/>
<tool separator="true"/>
<tool name="Indent"/>
<tool name="Outdent"/>
<tool separator="true"/>
<tool name="InsertOrderedList"/>
<tool name="InsertUnorderedList"/>
<tool separator="true"/>
<tool name="InsertLink" shortcut="CTRL+K"/>
<tool name="InsertSymbol"/>
</tools>
<tools name="DropdownToolbar">
<tool name="FontName"/>
<tool name="RealFontSize" text="Size"/>
</tools>
<tools enabled="true">
<tool name="Undo" shortcut="CTRL+Z"/>
<tool name="Redo" shortcut="CTRL+Y"/>
<tool separator="true"/>
<tool name="Cut" shortcut="CTRL+X"/>
<tool name="Copy" shortcut="CTRL+C"/>
<tool name="Paste" shortcut="CTRL+V"/>
<tool name="PastePlainText"/>
<tool separator="true"/>
<tool name="Print" shortcut="CTRL+P"/>
<tool name="FindAndReplace" shortcut="CTRL+F"/>
<tool name="SelectAll" shortcut="CTRL+A"/>
<tool separator="true"/>
<tool name="ToggleScreenMode" shortcut="F11"/>
</tools>
</root>