When you have a ToolBar that contains ComboBoxes inside, when resizing is made and overflow menu was created, it adds all the components that doesn't fit in. If Component is a ComboBox it doesn't add it to the menu.

This could be related in some way with this bug: http://www.sencha.com/forum/showthread.php?202902

But because I'm not sure I decided to open a new thread, feel free to merge both if you think you have to.