Hehe... Looking at it now actually... Does not look like Ext.AbstractComponent contains code to "init" the plugings like you find in Ext JS 4 version.

if (me.plugins) { me.plugins = [].concat(me.plugins); for (i = 0, len = me.plugins.length; i < len; i++) { me.plugins[i] = me.initPlugin(me.plugins[i]); } }