Preview button added to: clipfix, delay, highpass, lowpass, notch, tremolo, vocalremover and vocoder effects.

plug-ins/clipfix.ny

@@ -1,6 +1,7 @@
 ;nyquist plug-in
 ;version 1
 ;type process
+;preview enabled
 ;categories "http://audacityteam.org/namespace#NoiseRemoval"
 ;name "Clip Fix..."
 ;action "Reconstructing clips..."

plug-ins/delay.ny

@@ -1,6 +1,7 @@
 ;nyquist plug-in
 ;version 3
 ;type process
+;preview enabled
 ;categories "http://lv2plug.in/ns/lv2core#DelayPlugin"
 ;name "Delay..."
 ;action "Applying Delay Effect..."

plug-ins/highpass.ny

@@ -1,6 +1,7 @@
 ;nyquist plug-in
 ;version 3
 ;type process
+;preview enabled
 ;categories "http://lv2plug.in/ns/lv2core#HighpassPlugin"
 ;name "High Pass Filter..."
 ;action "Performing High Pass Filter..."

plug-ins/lowpass.ny

@@ -1,6 +1,7 @@
 ;nyquist plug-in
 ;version 3
 ;type process
+;preview enabled
 ;categories "http://lv2plug.in/ns/lv2core#LowpassPlugin"
 ;name "Low Pass Filter..."
 ;action "Performing Low Pass Filter..."

plug-ins/notch.ny

@@ -1,6 +1,7 @@
 ;nyquist plug-in
 ;version 1
 ;type process
+;preview enabled
 ;categories "http://lv2plug.in/ns/lv2core/#FilterPlugin"
 ;name "Notch Filter..."
 ;action "Performing Notch Filter..."

plug-ins/tremolo.ny

@@ -1,6 +1,7 @@
 ;nyquist plug-in
 ;version 3
 ;type process
+;preview enabled
 ;categories "http://lv2plug.in/ns/lv2core#ModulatorPlugin"
 ;name "Tremolo..."
 ;action "Applying Tremolo..."

plug-ins/vocalremover.ny

@@ -1,6 +1,7 @@
 ;nyquist plug-in
 ;version 3
 ;type process
+;preview enabled
 ;categories "http://lv2plug.in/ns/lv2core#UtilityPlugin"
 ;name "Vocal Remover (for center-panned vocals)..."
 ;action "Removing vocals or other center-panned audio..."

plug-ins/vocoder.ny

@@ -1,6 +1,7 @@
 ;nyquist plug-in
 ;version 3
 ;type process
+;preview enabled
 ;categories "http://lv2plug.in/ns/lv2core#SpectralPlugin"
 ;name "Vocoder..."
 ;action "Processing Vocoder..."