I just installed PSE10 last week and I have been having off and on issues with it! I am familar with PSE, as I have PSE7 for 2 years, so I know it is not product knowledge problem.
Hard to descibe, but for example, if I am trying to bandage a blemish, I use the tool, and click on the blemish...and then way off in the corner, or where ever the cursor feels like...it draws all on its own. Same happens in clone, or paint or burn, or ANYTHING! its super annoying, frustrating and isn't at all what I am commanding the cursor to do! I still have PSE7 on my computer and it DOES NOT do this to me! It's not a mouse issue as I have replaced the batteries and it still does this in PSE10, but not 7...and the even more annoying part...it does it SOMETIMES. Not all the time, just when you think its working great-BAM!- there is goes and screws up again.
I just reopened my PSE10 and reset tools. That seems to be working! I just don't trust it though! I will see if it glitches again and I will try the reset tools and I hope that's all it needs! Thank you so much for your quick response!
The general thing to do when PSE misbehaves is to reset the program's Preferences:
Hold down the Ctrl+Alt+Shift keys when launching the Editor and answer "Yes" to the prompt about deleting the Preferences. They will be re-built when PSE starts.