Lube your cable and brifter internals. Could be a bit of gunk clogging up the release mechanism in the shifter itself.
Edit: also lube all the joints on your front mech after spraying some WD-40 in there whilst moving the cage by hand.
__________________
Matt
2018 Enigma Excel Pic|| 2010 Kinesis Decade Convert2 Pic || 2008 Kinesis RC2 Pics || 2007 Kinesis Pha5e Pics || 2005 Kinesis RC Pics || 1996 Raleigh Max Pics