long pressing the x will minimize and not close apps. I'm pretty sure this setting can be changed in Start Menu>System Tools>uTask. I've never set it to only minimize, so I'm not sure exactly where in the utask settings that would be and since I don't currently have a TP2, I can't find out for you, but I'm pretty sure there is a way. If you find it, report back in case someone else also wants to know. Thanks!
Here a little tut. on utask in case you missed it:
http://forum.ppcgeeks.com/2044564-post2029.html
Actually now that I re-read that post I linked, go to : "Keys" at the bottom, on that page choose: "Close Key". Once you've highlighted "Close Key" go to the "Configure Key" tab at the bottom. I believe there you will find the option to make the x/close button close or minimize apps.