Oh! Sorry. Forgot to say why I've posted in this topic.
I use PRoC BLE module with BLE Pioneer Kit =)
An excerpt from the Cypress example-project for CapSense slider shows
/*If finger is detected on the slider*/
if(sliderPosition != NO_FINGER)
/* If finger position on the slider is changed then update the LED color */
if(sliderPosition != lastPosition)
where NO_FINGER is #defined as 0xffff
This is probably something you've missed.