Iphone 4 Messaging glitch!!!

I think ive found a glitch in the Iphone 4 messaging menu, ive tested this on two iphone 4's both have the problem but also tested it on the 3gs with no problem
Go to the Messaging menu and at the top its got the search field, type in it a name or phrase of text message, then messages will appear below it, touch on any message, then it will bring up that message, touch on the the box where it brings/shows the keyboard and now touch the message button that will go back a page, once that click on the home button (so your on the desktop) now go back into the message menu and now you should see in the middle of the screen the keyboad strip still there?!?!