If set treelist.micro = true, and use filtered store, on mouse over I get errors in console, and UI get broken (tooltips not shown, change micro mode impossible, etc).
The issue is serious, as this treelist is used in ext-gen generated application, and if someone want to hide some main menu items using store.filters he'll get broken UI.
Reproduced in this fiddle https://fiddle.sencha.com/#view/editor&fiddle/33u1