Why doesn't the FX Send or Fader Follow button work?

When pressing the Fader Follow button for a FX Send, nothing happens.
 

There is no FX Return channel assigned to that FX.

FX Return channels (light blue fader glow) must be assigned to enable the FX Send Fader Follow to function.  If there is no return channel assigned (Stereo Input 5 through 8 [ST 5 - ST 8] by default), the Send button will not operate.

Select the stereo channel you want for the FX return, in this example we are using ST 5.  Notice in the image below how there is no input patch assigned?  The fader glow is purple, meaning it is a non-fx stereo channel.  In this state, pushing the FX 1 Send Fader Follow button will do nothing, as FX 1 return is not assigned anywhere.

The image below shows the LEX-RT1 assigned to the ST 5 channel.  Now the FX 1 button, and the FX engine itself, will operate.

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