[BROWSEUI] explorer crash - addressbar combobox must not receive mouse-scroll events when being collapsed

tested ros gcc dbg 0.4.8-dev-450.

In explorer file browser there is an addressbar.

Expected behavior:
When addressbar is collapsed state it must not receive any mouse scroll events.

Observed behavior:
It receives scroll events even in collapsed state.

This is not only very unintuitive, but it may even crash explorer as can be seen in video.webm.
In 0.4.8-dev-450-gad181d8.log the crash happened right above

(../win32ss/user/ntuser/message.c:1264) err: Attempted to post message to window 003C0104 when the thread is in cleanup!