I keep running into situations where config options are not listed in the API browser since they are not annotated in the source code. As an example Ext.chart.Chart specifies 'series' and a 'store' configuration but these are not annotated in the source code and displayed as config options in the API browser. This makes it very hard to find out which configurations that may actually be passed.
The list for Ext.panel.Tool's handler config isn't correct in the arguments that are passed. The third argument is an Ext.panel.Header, not an Ext.panel.Panel. This is different from ExtJS 3 where it was the Ext.Panel that contained the tool.