Ask HN: Is it bad usability to have search be part of a vertical drop down menu?

Working on something that has a series of vertical drop down menus. A selection made in the first menu shows a second menu with selections that are children of the parent selection in the first menu Similarly, selecting an item in the 2nd menu shows a 3rd menu with items that are children of the selection in the 2nd menu and so on.

Ultimately, whichever child level you choose to stop at and click submit that would show you filtered search results based on the selections in the parent and child(ren) level(s).

However, after a point in time, it can get cumbersome to have to make selections in successive menus if you already know which child menu your selection is in so that you can get to the search results you want quickly.

Thinking of implementing a search bar directly in the parent (1st) vertical drop down. The idea is that you could type in this bar and it would reveal all the menu navigation paths that contained the keywords you typed. You could then simply select the path that applied best and reveal the search results matching that path.

I've just never seen something like this implemented elsewhere and was wondering whether that was because it was considered as bad usability or some other reason.

Hope that all made sense.

Thanks!