diff --git a/gtk2_ardour/themes/blueberry_milk-ardour.colors b/gtk2_ardour/themes/blueberry_milk-ardour.colors
index 21b7d4ad73..884f2790ab 100644
--- a/gtk2_ardour/themes/blueberry_milk-ardour.colors
+++ b/gtk2_ardour/themes/blueberry_milk-ardour.colors
@@ -93,7 +93,7 @@
     <ColorAlias name="feedback alert: led active" alias="alert:red"/>
     <ColorAlias name="foldback knob" alias="widget:bg"/>
     <ColorAlias name="foldback knob: fill" alias="widget:bg"/>
-    <ColorAlias name="foldback knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="foldback knob: arc end" alias="widget:blue"/>
     <ColorAlias name="foldback knob: arc start" alias="widget:blue"/>
     <ColorAlias name="frame handle" alias="theme:bg1"/>
     <ColorAlias name="gain line" alias="alert:blue"/>
@@ -249,7 +249,7 @@
     <ColorAlias name="monitor section dim: fill active" alias="alert:orange"/>
     <ColorAlias name="monitor section dim: led active" alias="alert:blue"/>
     <ColorAlias name="monitor section knob" alias="widget:bg"/>
-    <ColorAlias name="monitor section knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="monitor section knob: arc end" alias="widget:blue"/>
     <ColorAlias name="monitor section knob: arc start" alias="widget:blue"/>
     <ColorAlias name="monitor section mono: fill" alias="widget:bg"/>
     <ColorAlias name="monitor section mono: fill active" alias="alert:blue"/>
@@ -309,8 +309,8 @@
     <ColorAlias name="processor control button: fill" alias="neutral:background"/>
     <ColorAlias name="processor control button: fill active" alias="neutral:background2"/>
     <ColorAlias name="processor control button: led active" alias="widget:blue"/>
-    <ColorAlias name="processor control knob" alias="theme:contrasting selection"/>
-    <ColorAlias name="processor control knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="processor control knob" alias="theme:bg"/>
+    <ColorAlias name="processor control knob: arc end" alias="widget:blue"/>
     <ColorAlias name="processor control knob: arc start" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill active" alias="widget:blue"/>
@@ -453,8 +453,8 @@
     <ColorAlias name="trim handle" alias="alert:blue"/>
     <ColorAlias name="trim handle locked" alias="alert:ruddy"/>
     <ColorAlias name="trim knob" alias="widget:bg"/>
-    <ColorAlias name="trim knob: arc end" alias="alert:blue"/>
-    <ColorAlias name="trim knob: arc start" alias="widget:bg"/>
+    <ColorAlias name="trim knob: arc end" alias="widget:blue"/>
+    <ColorAlias name="trim knob: arc start" alias="widget:blue"/>
     <ColorAlias name="vca assign button: fill" alias="widget:bg"/>
     <ColorAlias name="verbose canvas cursor" alias="theme:contrasting clock"/>
     <ColorAlias name="video timeline bar" alias="neutral:background2"/>
diff --git a/gtk2_ardour/themes/caineville-ardour.colors b/gtk2_ardour/themes/caineville-ardour.colors
index 1586864d5d..583f7b08bf 100644
--- a/gtk2_ardour/themes/caineville-ardour.colors
+++ b/gtk2_ardour/themes/caineville-ardour.colors
@@ -94,7 +94,7 @@
     <ColorAlias name="feedback alert: led active" alias="alert:red"/>
     <ColorAlias name="foldback knob" alias="widget:bg"/>
     <ColorAlias name="foldback knob: fill" alias="widget:bg"/>
-    <ColorAlias name="foldback knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="foldback knob: arc end" alias="widget:blue"/>
     <ColorAlias name="foldback knob: arc start" alias="widget:blue"/>
     <ColorAlias name="frame handle" alias="theme:bg1"/>
     <ColorAlias name="gain line" alias="alert:green"/>
@@ -250,7 +250,7 @@
     <ColorAlias name="monitor section dim: fill active" alias="alert:orange"/>
     <ColorAlias name="monitor section dim: led active" alias="alert:green"/>
     <ColorAlias name="monitor section knob" alias="widget:bg"/>
-    <ColorAlias name="monitor section knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="monitor section knob: arc end" alias="widget:blue"/>
     <ColorAlias name="monitor section knob: arc start" alias="widget:blue"/>
     <ColorAlias name="monitor section mono: fill" alias="widget:bg"/>
     <ColorAlias name="monitor section mono: fill active" alias="alert:blue"/>
@@ -310,8 +310,8 @@
     <ColorAlias name="processor control button: fill" alias="neutral:background"/>
     <ColorAlias name="processor control button: fill active" alias="neutral:background2"/>
     <ColorAlias name="processor control button: led active" alias="widget:blue"/>
-    <ColorAlias name="processor control knob" alias="theme:contrasting selection"/>
-    <ColorAlias name="processor control knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="processor control knob" alias="theme:bg"/>
+    <ColorAlias name="processor control knob: arc end" alias="widget:blue"/>
     <ColorAlias name="processor control knob: arc start" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill active" alias="widget:blue"/>
@@ -454,8 +454,8 @@
     <ColorAlias name="trim handle" alias="alert:blue"/>
     <ColorAlias name="trim handle locked" alias="alert:ruddy"/>
     <ColorAlias name="trim knob" alias="widget:bg"/>
-    <ColorAlias name="trim knob: arc end" alias="alert:blue"/>
-    <ColorAlias name="trim knob: arc start" alias="widget:bg"/>
+    <ColorAlias name="trim knob: arc end" alias="widget:blue"/>
+    <ColorAlias name="trim knob: arc start" alias="widget:blue"/>
     <ColorAlias name="vca assign button: fill" alias="widget:bg"/>
     <ColorAlias name="verbose canvas cursor" alias="theme:contrasting clock"/>
     <ColorAlias name="video timeline bar" alias="neutral:background2"/>
diff --git a/gtk2_ardour/themes/clear_gray-ardour.colors b/gtk2_ardour/themes/clear_gray-ardour.colors
index cd9dd26fa2..f2a08c6b1f 100644
--- a/gtk2_ardour/themes/clear_gray-ardour.colors
+++ b/gtk2_ardour/themes/clear_gray-ardour.colors
@@ -94,7 +94,7 @@
     <ColorAlias name="feedback alert: led active" alias="alert:red"/>
     <ColorAlias name="foldback knob" alias="widget:bg"/>
     <ColorAlias name="foldback knob: fill" alias="widget:bg"/>
-    <ColorAlias name="foldback knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="foldback knob: arc end" alias="widget:blue"/>
     <ColorAlias name="foldback knob: arc start" alias="widget:blue"/>
     <ColorAlias name="frame handle" alias="theme:bg1"/>
     <ColorAlias name="gain line" alias="alert:green"/>
@@ -250,7 +250,7 @@
     <ColorAlias name="monitor section dim: fill active" alias="alert:orange"/>
     <ColorAlias name="monitor section dim: led active" alias="alert:green"/>
     <ColorAlias name="monitor section knob" alias="widget:bg"/>
-    <ColorAlias name="monitor section knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="monitor section knob: arc end" alias="widget:blue"/>
     <ColorAlias name="monitor section knob: arc start" alias="widget:blue"/>
     <ColorAlias name="monitor section mono: fill" alias="widget:bg"/>
     <ColorAlias name="monitor section mono: fill active" alias="alert:blue"/>
@@ -310,8 +310,8 @@
     <ColorAlias name="processor control button: fill" alias="neutral:background"/>
     <ColorAlias name="processor control button: fill active" alias="neutral:background2"/>
     <ColorAlias name="processor control button: led active" alias="widget:blue"/>
-    <ColorAlias name="processor control knob" alias="theme:contrasting selection"/>
-    <ColorAlias name="processor control knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="processor control knob" alias="theme:bg"/>
+    <ColorAlias name="processor control knob: arc end" alias="widget:blue"/>
     <ColorAlias name="processor control knob: arc start" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill active" alias="widget:blue"/>
@@ -454,8 +454,8 @@
     <ColorAlias name="trim handle" alias="alert:blue"/>
     <ColorAlias name="trim handle locked" alias="alert:ruddy"/>
     <ColorAlias name="trim knob" alias="widget:bg"/>
-    <ColorAlias name="trim knob: arc end" alias="alert:blue"/>
-    <ColorAlias name="trim knob: arc start" alias="widget:bg"/>
+    <ColorAlias name="trim knob: arc end" alias="widget:blue"/>
+    <ColorAlias name="trim knob: arc start" alias="widget:blue"/>
     <ColorAlias name="vca assign button: fill" alias="widget:bg"/>
     <ColorAlias name="verbose canvas cursor" alias="theme:contrasting clock"/>
     <ColorAlias name="video timeline bar" alias="neutral:background2"/>
diff --git a/gtk2_ardour/themes/cubasish-ardour.colors b/gtk2_ardour/themes/cubasish-ardour.colors
index d93779e915..5a645acafd 100644
--- a/gtk2_ardour/themes/cubasish-ardour.colors
+++ b/gtk2_ardour/themes/cubasish-ardour.colors
@@ -94,7 +94,7 @@
     <ColorAlias name="feedback alert: led active" alias="alert:red"/>
     <ColorAlias name="foldback knob" alias="widget:bg"/>
     <ColorAlias name="foldback knob: fill" alias="widget:bg"/>
-    <ColorAlias name="foldback knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="foldback knob: arc end" alias="widget:blue"/>
     <ColorAlias name="foldback knob: arc start" alias="widget:blue"/>
     <ColorAlias name="frame handle" alias="theme:bg1"/>
     <ColorAlias name="gain line" alias="alert:green"/>
@@ -250,7 +250,7 @@
     <ColorAlias name="monitor section dim: fill active" alias="alert:orange"/>
     <ColorAlias name="monitor section dim: led active" alias="alert:green"/>
     <ColorAlias name="monitor section knob" alias="widget:bg"/>
-    <ColorAlias name="monitor section knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="monitor section knob: arc end" alias="widget:blue"/>
     <ColorAlias name="monitor section knob: arc start" alias="widget:blue"/>
     <ColorAlias name="monitor section mono: fill" alias="widget:bg"/>
     <ColorAlias name="monitor section mono: fill active" alias="alert:blue"/>
@@ -310,8 +310,8 @@
     <ColorAlias name="processor control button: fill" alias="neutral:background"/>
     <ColorAlias name="processor control button: fill active" alias="neutral:background2"/>
     <ColorAlias name="processor control button: led active" alias="widget:blue"/>
-    <ColorAlias name="processor control knob" alias="theme:contrasting selection"/>
-    <ColorAlias name="processor control knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="processor control knob" alias="theme:bg"/>
+    <ColorAlias name="processor control knob: arc end" alias="widget:blue"/>
     <ColorAlias name="processor control knob: arc start" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill active" alias="widget:blue"/>
@@ -454,8 +454,8 @@
     <ColorAlias name="trim handle" alias="alert:blue"/>
     <ColorAlias name="trim handle locked" alias="alert:ruddy"/>
     <ColorAlias name="trim knob" alias="widget:bg"/>
-    <ColorAlias name="trim knob: arc end" alias="alert:blue"/>
-    <ColorAlias name="trim knob: arc start" alias="widget:bg"/>
+    <ColorAlias name="trim knob: arc end" alias="widget:blue"/>
+    <ColorAlias name="trim knob: arc start" alias="widget:blue"/>
     <ColorAlias name="vca assign button: fill" alias="widget:bg"/>
     <ColorAlias name="verbose canvas cursor" alias="theme:contrasting clock"/>
     <ColorAlias name="video timeline bar" alias="neutral:background2"/>
diff --git a/gtk2_ardour/themes/dark-ardour.colors b/gtk2_ardour/themes/dark-ardour.colors
index 4f86199661..45074f68da 100644
--- a/gtk2_ardour/themes/dark-ardour.colors
+++ b/gtk2_ardour/themes/dark-ardour.colors
@@ -94,7 +94,7 @@
     <ColorAlias name="feedback alert: led active" alias="alert:red"/>
     <ColorAlias name="foldback knob" alias="widget:bg"/>
     <ColorAlias name="foldback knob: fill" alias="widget:bg"/>
-    <ColorAlias name="foldback knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="foldback knob: arc end" alias="widget:blue"/>
     <ColorAlias name="foldback knob: arc start" alias="widget:blue"/>
     <ColorAlias name="frame handle" alias="theme:bg1"/>
     <ColorAlias name="gain line" alias="alert:green"/>
@@ -250,7 +250,7 @@
     <ColorAlias name="monitor section dim: fill active" alias="alert:orange"/>
     <ColorAlias name="monitor section dim: led active" alias="alert:green"/>
     <ColorAlias name="monitor section knob" alias="widget:bg"/>
-    <ColorAlias name="monitor section knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="monitor section knob: arc end" alias="widget:blue"/>
     <ColorAlias name="monitor section knob: arc start" alias="widget:blue"/>
     <ColorAlias name="monitor section mono: fill" alias="widget:bg"/>
     <ColorAlias name="monitor section mono: fill active" alias="alert:blue"/>
@@ -310,8 +310,8 @@
     <ColorAlias name="processor control button: fill" alias="neutral:background"/>
     <ColorAlias name="processor control button: fill active" alias="neutral:background2"/>
     <ColorAlias name="processor control button: led active" alias="widget:blue"/>
-    <ColorAlias name="processor control knob" alias="theme:contrasting selection"/>
-    <ColorAlias name="processor control knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="processor control knob" alias="theme:bg"/>
+    <ColorAlias name="processor control knob: arc end" alias="widget:blue"/>
     <ColorAlias name="processor control knob: arc start" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill active" alias="widget:blue"/>
@@ -454,8 +454,8 @@
     <ColorAlias name="trim handle" alias="alert:blue"/>
     <ColorAlias name="trim handle locked" alias="alert:ruddy"/>
     <ColorAlias name="trim knob" alias="widget:bg"/>
-    <ColorAlias name="trim knob: arc end" alias="alert:blue"/>
-    <ColorAlias name="trim knob: arc start" alias="widget:bg"/>
+    <ColorAlias name="trim knob: arc end" alias="widget:blue"/>
+    <ColorAlias name="trim knob: arc start" alias="widget:blue"/>
     <ColorAlias name="vca assign button: fill" alias="widget:bg"/>
     <ColorAlias name="verbose canvas cursor" alias="theme:contrasting clock"/>
     <ColorAlias name="video timeline bar" alias="neutral:background2"/>
diff --git a/gtk2_ardour/themes/unastudia-ardour.colors b/gtk2_ardour/themes/unastudia-ardour.colors
index c50073b29e..f1e471e29c 100644
--- a/gtk2_ardour/themes/unastudia-ardour.colors
+++ b/gtk2_ardour/themes/unastudia-ardour.colors
@@ -93,7 +93,7 @@
     <ColorAlias name="feedback alert: led active" alias="alert:red"/>
     <ColorAlias name="foldback knob" alias="widget:bg"/>
     <ColorAlias name="foldback knob: fill" alias="widget:bg"/>
-    <ColorAlias name="foldback knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="foldback knob: arc end" alias="widget:blue"/>
     <ColorAlias name="foldback knob: arc start" alias="widget:blue"/>
     <ColorAlias name="frame handle" alias="theme:bg1"/>
     <ColorAlias name="gain line" alias="alert:blue"/>
@@ -249,7 +249,7 @@
     <ColorAlias name="monitor section dim: fill active" alias="alert:orange"/>
     <ColorAlias name="monitor section dim: led active" alias="alert:blue"/>
     <ColorAlias name="monitor section knob" alias="widget:bg"/>
-    <ColorAlias name="monitor section knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="monitor section knob: arc end" alias="widget:blue"/>
     <ColorAlias name="monitor section knob: arc start" alias="widget:blue"/>
     <ColorAlias name="monitor section mono: fill" alias="widget:bg"/>
     <ColorAlias name="monitor section mono: fill active" alias="alert:blue"/>
@@ -309,8 +309,8 @@
     <ColorAlias name="processor control button: fill" alias="neutral:background"/>
     <ColorAlias name="processor control button: fill active" alias="neutral:background2"/>
     <ColorAlias name="processor control button: led active" alias="widget:blue"/>
-    <ColorAlias name="processor control knob" alias="theme:contrasting selection"/>
-    <ColorAlias name="processor control knob: arc end" alias="alert:blue"/>
+    <ColorAlias name="processor control knob" alias="theme:bg"/>
+    <ColorAlias name="processor control knob: arc end" alias="widget:blue"/>
     <ColorAlias name="processor control knob: arc start" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill" alias="widget:blue"/>
     <ColorAlias name="processor fader: fill active" alias="widget:blue"/>
@@ -453,8 +453,8 @@
     <ColorAlias name="trim handle" alias="alert:blue"/>
     <ColorAlias name="trim handle locked" alias="alert:ruddy"/>
     <ColorAlias name="trim knob" alias="widget:bg"/>
-    <ColorAlias name="trim knob: arc end" alias="alert:blue"/>
-    <ColorAlias name="trim knob: arc start" alias="widget:bg"/>
+    <ColorAlias name="trim knob: arc end" alias="widget:blue"/>
+    <ColorAlias name="trim knob: arc start" alias="widget:blue"/>
     <ColorAlias name="vca assign button: fill" alias="widget:bg"/>
     <ColorAlias name="verbose canvas cursor" alias="theme:contrasting clock"/>
     <ColorAlias name="video timeline bar" alias="neutral:background2"/>