Anyone seen strange "find-in-project" issues in Xcode 7?

I have OSX El Cap installed on two partitions. The first is my original partition that has been my development iMac since 2011. I recently created a new smaller partition with the intent of having it as a minimal fresh install
of El Capitan. However when i boot off this partition - which seems fine in all other regards - and launch Xcode in order to work on some C++ projects
I find I can build, compile etc… but whenever I try to use “Find In Project” to search for some word - nothing happens. For any of my projects.

I have Xcode 7.3.1 installed on this second partition and 7.3 on the original partition - but makes no difference. If I boot off the original partition i can do “Find In Project” fine using either version of the app. But if i boot off the new partition and try to do the same - Find In Project ceases to work.

The text entry area where one types the search criteria also behaves strangely - almost as if its a multi-line text field instead of a simple one-line text field.

Steps to Reproduce:
on same hard disk as where Xcode and all your development projects are stored, create a second partition and make it bootable as OSX and install El Capitan on it.

Boot off the new partition and then launch Xcode - open some project on th original partition and see if you can do a “Find in project”

Expected Results:
searches project and lists match results

Actual Results:
does nothing.