Closing Apps-Touch Screen Sensitivity-Red Dash -

I double click the home button, from the home screen, this bring up my current running apps

I press and hold one of the icons until they shake and i see a small badge show up on each, a red [-] sign used to close out the apps

I'm having an issue with the sensitivity of the touch screen when closing out apps, by pressing the red minus sign

Only at the bottom of the screen, and only when closing out apps the touch screen seems to respond correctly about 50 percent of the time

What's the deal? Anyone else with the same issue?

The bottom of the screen seems fine, for touch sensitivity when pressing anything else that happens to be at the bottom of the screen, so it doesn't seem like a hardware failure.