according to ExtJS you can use rtl:true for mirroring right to left
does Ext.Net 2.1 support this ?
How to use this property with Ext.Net ?
UPDATE As answered , it's not yet supported but I found this css and js to be very useful
As mentioned by @sra, RTL support is being introduced in ExtJS 4.2, which is currently in Beta release. The current build of Ext.NET (2.2) in SVN includes the most recent Ext JS 4.2 Beta release. There are several samples in the Ext.NET 2.2 Examples Explorer which demonstrate the new RTL support.
The final release of Ext.NET 2.2 will include the final release of Ext JS 4.2.
Hope this helps.