I use find and replace a lot, and it closes after every "replace all" action.
It does not close after "find" or "replace", I find it difficult to understand why the program would close a panel someone was working in by default and offer no option to not close the panel?
Maybe add a checkbox or a little pin icon to stick the panel open?
I see this topic was brought up as a feature request in 2012. Apparently not very high demand.