Comment 3 for bug 1300789

These errors appear because the javascript file(s) the patron search form references likely aren't fully loaded by the time you quickly hit F3 to switch to catalog search, after realizing your mistake.

I have a sneaking suspicion that a "long press" prompts a refresh (appears to refresh the F3 page) which is why the symptoms are the same on a long press. The javascript hasn't loaded/grabbed all of the strings for the form before you "sever" the connection to perform a refresh.

Maybe the solution is to open new tabs for each unique "F-key", or maybe even a new tab no matter what F-key you press.