there is a bug when you have a toolbar that has the overflow menu enabled, there is a _tbfill_ and you try to show on of the toolbars components in the _afterlayout_ listener. I created a fiddle to showcase the bug: https://fiddle.sencha.com/#view/editor&fiddle/3102
The bug occurs in all versions.
My current workaround is to disable the hide function of the _tbfill_ component, which works but is not really nice...