This may or may not be fixed in the SVN tree, but since I don't have access to that I can neither confirm nor deny, and thus I am submitting this as a bug report.
Version: Ext JS Library 3.0 RC 1.1
I created a ComboBox with mode: remote and a JsonStore store.
When clicking the trigger the dropdown appears with the spinner and the "Loading..." text.
Using Firebug I can confirm that the remote data script was properly called, and returned the below quoted data.
Tracing through the Ext JS code I've found that the Ext.data.Store.loadRecords() call to this.fireEvent("datachanged", this) fails to call the registered 'datachanged' function Ext.DataView.refresh(). (This is registered in Ext.DataView.bindStore())
Inside the EXTUTIL.Observable.prototype.fireEvent call for 'datachanged' the 'ce' parameter is set to the boolean value of 'true' and NOT an object -- causing the ce.fire.apply(ce,a) call to be skipped.
The creation of my ComboBox:
I have two methods by which I've tried to create the ComboBox -- both exhibited the SAME behavior.
Well, now that you put it that way -- apparently I hadn't tried that specific permutation. That fixed my problem. I'll comment my code to try the xtype method when you release the next RC or the final 3.0