GLSL spec [1.30 - 1.40] section 4.5.3 states that fragment program requires a [default] precision for float values. Failure to do so, causes a bug as reported here: <http://forum.jogamp.org/quot-Shader-status-invalid-quot-with-latest-jars-and-GLJpanel-td4029177.html>
Note: GLSL spec >= 1.50 does _not_ require such default precision.
Needs verification on said machines w/ GLSL [1.30 - 1.40] which failed!