The TypeCommand type brings up a full notepad-esque interface.

http://i.imgur.com/fB44GBl.png

Engine/source/gui/core/guiControl.cpp

@@ -270,11 +270,11 @@ void GuiControl::initPersistFields()
 
       addField("variable",          TypeString,       Offset(mConsoleVariable, GuiControl),
          "Name of the variable to which the value of this control will be synchronized." );
-      addField("command",           TypeRealString,   Offset(mConsoleCommand, GuiControl),
+      addField("command",           TypeCommand,   Offset(mConsoleCommand, GuiControl),
          "Command to execute on the primary action of the control.\n\n"
          "@note Within this script snippet, the control on which the #command is being executed is bound to "
             "the global variable $ThisControl." );
-      addField("altCommand",        TypeRealString,   Offset(mAltConsoleCommand, GuiControl),
+      addField("altCommand",        TypeCommand,   Offset(mAltConsoleCommand, GuiControl),
          "Command to execute on the secondary action of the control.\n\n"
          "@note Within this script snippet, the control on which the #altCommand is being executed is bound to "
             "the global variable $ThisControl." );