Found bug in Ext.mixin.Container.attachNameRef
Here is such code:
Code:
if (!entry) {                    entry = component.shareableName ? [component] : component;
                }
                else if (!entry.isInstance) {
                    // Else an existing entry is either a component (which will have false
                    // for shareableName) or an array (all elements of which have true
                    // for their shareableName).
                    entry.push(component);
                }
                //<debug>
                else {
                        Ext.raise('Duplicate name: "' + key + '" on ' +
                            me.id + ' between ' + entry.id + ' and ' + component.id);
                }
                //</debug>
And for me in several applications it Raises exception about Duplicate name, but entry and component is the same, so obviously it shouldn't cry.

To hide this exception for me worked to add:

Code:
                    if(entry !== component) {
                        Ext.raise('Duplicate name: "' + key + '" on ' +
                            me.id + ' between ' + entry.id + ' and ' + component.id);
                    }