Using just the touchpad start a selection in i.e gedit. Right after you finish the selection make a quick click. This should remove the selection and place the cursor in that point, instead the selection will stay. If instead you add the selection, wait a bit and then do the click, the selection will disappear and it will behave properly. I guess this is some kind of time out cancelling the selection. Let me know if you need any logs.
*** This bug has been marked as a duplicate of bug 90928 ***
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.