Trackpad Sticking (cursor grabs an item and doesn't let go)

I'm having problems with my MacBook pro trackpad "sticking" for want of a better word. Every now and again when I place my cursor over things the cursor grabs the item and won't let go whatever I try to do.

It seems to have been getting worse over the last week or so. Just wondering if this is a known fault, or whether I've missed a setting in the trackpad control panel that might fix this.

Also, in Photoshop I've been noticing a compass occasionally appearing at the centre of the window without me doing anything. I've never seen this compass before - not even sure if it's a Photoshop thing or system wide. Anyone know?

Thanls!