Search ("Find...") bar shifts the lower window text in horizontal split mode

[Ripley6811]

With "Horizontal Split" mode on, the text in the lower window shifts up one line when the search box appears and then shifts back when the search box disappears.

This can be a little annoying when we go from using search to trying to click or select something in the lower window. It would be better if it didn't shift at all.

Occurs without extensions and I'm using 1.4 build 1.4.0-16380 (release 273804e)