This article explains how to keep the touch active in push-to-talk apps

Starting with Elo Windows Multi-Touch driver version 7.2.1, when Elo touch device is configured as a digitizer (which is the default installation configuration), if users choose “Click on Release” with “Enable Drag”, the users can press and hold a button without the need to wiggle/shift/roll finger to activate Windows button down event.

Please note, on Windows7/8.1, the user needs to turn off “Flick” gesture to make the above feature to work as designed.