The Tracker 5.0.7 upgrade is here and I recommend that you upgrade before the Fall term. This upgrade improves image quality for perspective and radial distortion filters, gracefully accepts either comma or period decimal separators in all locales, and greatly speeds up loading of some TRK files.
To upgrade, click the green "Now available" button on the toolbar and choose Upgrade Now. If you don't see the button choose Help|Check For Upgrades.
Full installers are also available for Windows, Mac and Linux from both the Tracker home page (http://physlets.org/tracker/) and ComPADRE (http://www.opensourcephysics.org/items/detail.cfm?ID=7365).
As always, I encourage you to ask questions and/or report issues on this forum :-) Doug