On the GeoExt website their tutorial page has some instructions on how to setup up a application to use GeoEXT. This is the page I am referring to.
It mentions that you should download GeoEXT 1.0 and ExtJS 3.2. I have since noticed that Sencha has released ExtJS 4. Can ExtJS 4 be used along side GeoEXT 1.0 without any issues? Or should I go by the book and install ExtJS 3.2?