* Fix rendering of TreeGrid's frozen columns after hierarchy-column reset (#12028)
* Add tests
* Fix getVisibleFrozenColumnCount() if SelectionMode is multi
* Update ComboBox popup position comparison to use correct top value. (#12041)
Fixes #12029
* Clear thread local instances on connection lost in push handler (#12042)
Adopted from https://github.com/vaadin/flow/pull/8567
Co-authored-by: Tarek Oraby <42799254+tarekoraby@users.noreply.github.com>
Co-authored-by: Anna Koskinen <Ansku@users.noreply.github.com>
Co-authored-by: Tatu Lund <tatu@vaadin.com>