did you directly update to 5.0, i.e through an ota? If you did, clear data for talkback. This should fix this problem. As an alternative, enable single tap selection in talkback settings to get behavier similar to ics only when you directly touch an item, not by flicking. As a last resort, try turning talkback completely off then back on, which should reset the explore by touch preference in the settings database. To turn talkback back on, use the accessibility shortcut, which is press power until you hear a sound or feel a vibration and then place two fingers on the screen just like you did during the initial setup.