diff --git a/gtk2_ardour/themes/blueberry_milk-ardour.colors b/gtk2_ardour/themes/blueberry_milk-ardour.colors
index c3ffbcba59..36593b99dc 100644
--- a/gtk2_ardour/themes/blueberry_milk-ardour.colors
+++ b/gtk2_ardour/themes/blueberry_milk-ardour.colors
@@ -214,7 +214,6 @@
     <ColorAlias name="midi device: fill" alias="widget:bg"/>
     <ColorAlias name="midi device: fill active" alias="theme:bg"/>
     <ColorAlias name="midi device: led active" alias="alert:green"/>
-    <ColorAlias name="midi frame base" alias="neutral:background2"/>
     <ColorAlias name="midi input button: fill active" alias="alert:cyan"/>
     <ColorAlias name="midi input button: led active" alias="alert:red"/>
     <ColorAlias name="midi meter color0" alias="midi meter 52"/>
@@ -491,7 +490,6 @@
     <Modifier name="loop rectangle" modifier="= alpha:0.24"/>
     <Modifier name="marker bar" modifier="= alpha:0.5"/>
     <Modifier name="grid line" modifier="= alpha:1.0"/>
-    <Modifier name="midi frame base" modifier="= alpha:0.85"/>
     <Modifier name="midi note" modifier="= alpha:0.8"/>
     <Modifier name="midi note velocity text" modifier="= alpha:0.4666"/>
     <Modifier name="midi patch change fill" modifier="= alpha:0.6274"/>
diff --git a/gtk2_ardour/themes/caineville-ardour.colors b/gtk2_ardour/themes/caineville-ardour.colors
index 5c80cff859..2969784b74 100644
--- a/gtk2_ardour/themes/caineville-ardour.colors
+++ b/gtk2_ardour/themes/caineville-ardour.colors
@@ -19,7 +19,7 @@
     <Color name="theme:contrasting alt" value="f6ce10ff"/>  <!--secondary delta clock: text,  gtk_bg_tooltip,  selected region base,  location marker,  transport button: fill active-->
     <Color name="neutral:backgroundest" value="000000ff"/>  <!--border color,  audio master bus base,  time axis frame,  waveform outline,  stereo panner text-->
     <Color name="neutral:background" value="202020ff"/>  <!--audio track base,  gtk_fg_tooltip,  mono panner text,  processor postfader: fill-->
-    <Color name="neutral:background2" value="555555ff"/>  <!--range marker bar,  covered region,  tempo bar,  midi frame base-->
+    <Color name="neutral:background2" value="555555ff"/>  <!--range marker bar,  covered region,  tempo bar -->
     <Color name="neutral:midground" value="7f7f7fff"/>  <!--grid line minor,  grid line micro,  mono panner bg,  processor prefader: fill,  stereo panner mono bg,  ruler text-->
     <Color name="neutral:foreground2" value="b5b5b5ff"/>  <!--marker track,  gtk_light_text_on_dark,  piano roll white,  secondary clock: text-->
     <Color name="neutral:foreground" value="e5e5e5ff"/>  <!--gtk_foreground,  gtk_texts,  location loop,  selection rect,  transport loop rect-->
@@ -215,7 +215,6 @@
     <ColorAlias name="midi device: fill" alias="widget:bg"/>
     <ColorAlias name="midi device: fill active" alias="theme:bg"/>
     <ColorAlias name="midi device: led active" alias="alert:green"/>
-    <ColorAlias name="midi frame base" alias="neutral:background2"/>
     <ColorAlias name="midi input button: fill active" alias="theme:contrasting alt"/>
     <ColorAlias name="midi input button: led active" alias="alert:red"/>
     <ColorAlias name="midi meter color0" alias="midi meter 52"/>
@@ -492,7 +491,6 @@
     <Modifier name="loop rectangle" modifier="= alpha:0.5"/>
     <Modifier name="marker bar" modifier="= alpha:0.5"/>
     <Modifier name="grid line" modifier="= alpha:1.0"/>
-    <Modifier name="midi frame base" modifier="= alpha:0.85"/>
     <Modifier name="midi note" modifier="= alpha:0.8"/>
     <Modifier name="midi note velocity text" modifier="= alpha:0.4666"/>
     <Modifier name="midi patch change fill" modifier="= alpha:0.6274"/>
diff --git a/gtk2_ardour/themes/clear_gray-ardour.colors b/gtk2_ardour/themes/clear_gray-ardour.colors
index 18bb38639d..4e2926bb64 100644
--- a/gtk2_ardour/themes/clear_gray-ardour.colors
+++ b/gtk2_ardour/themes/clear_gray-ardour.colors
@@ -19,7 +19,7 @@
     <Color name="theme:contrasting alt" value="aa8e39ff"/>  <!--gtk_somewhat_bright_indicator,  rude isolate: fill active,  secondary delta clock: text-->
     <Color name="neutral:backgroundest" value="000000ff"/>  <!--border color,  automation line,  control point fill,  grid line major,  waveform outline-->
     <Color name="neutral:background" value="202020ff"/>  <!--audio track base,  processor control button: fill-->
-    <Color name="neutral:background2" value="555555ff"/>  <!--range marker bar,  covered region,  midi frame base,  recording waveform outline,  tempo bar-->
+    <Color name="neutral:background2" value="555555ff"/>  <!--range marker bar,  covered region, recording waveform outline,  tempo bar-->
     <Color name="neutral:midground" value="7f7f7fff"/>  <!--grid line minor,  ruler text-->
     <Color name="neutral:foreground2" value="ccccccff"/>  <!--marker track,  gtk_light_text_on_dark,  piano roll white,  secondary clock: text-->
     <Color name="neutral:foreground" value="e5e5e5ff"/>  <!--gtk_foreground,  gtk_bg_tooltip,  gtk_texts-->
@@ -215,7 +215,6 @@
     <ColorAlias name="midi device: fill" alias="widget:bg"/>
     <ColorAlias name="midi device: fill active" alias="theme:bg"/>
     <ColorAlias name="midi device: led active" alias="alert:green"/>
-    <ColorAlias name="midi frame base" alias="neutral:background2"/>
     <ColorAlias name="midi input button: fill active" alias="alert:ruddy"/>
     <ColorAlias name="midi input button: led active" alias="alert:red"/>
     <ColorAlias name="midi meter color0" alias="midi meter 52"/>
@@ -492,7 +491,6 @@
     <Modifier name="loop rectangle" modifier="= alpha:0.5"/>
     <Modifier name="marker bar" modifier="= alpha:0.5"/>
     <Modifier name="grid line" modifier="= alpha:1.0"/>
-    <Modifier name="midi frame base" modifier="= alpha:0.85"/>
     <Modifier name="midi note" modifier="= alpha:0.8"/>
     <Modifier name="midi note velocity text" modifier="= alpha:0.4666"/>
     <Modifier name="midi patch change fill" modifier="= alpha:0.6274"/>
diff --git a/gtk2_ardour/themes/cubasish-ardour.colors b/gtk2_ardour/themes/cubasish-ardour.colors
index 3d5f32e699..1f8c652821 100644
--- a/gtk2_ardour/themes/cubasish-ardour.colors
+++ b/gtk2_ardour/themes/cubasish-ardour.colors
@@ -19,7 +19,7 @@
     <Color name="theme:contrasting alt" value="cca336ff"/>  <!--secondary delta clock: text,  rude isolate: fill active-->
     <Color name="neutral:backgroundest" value="000000ff"/>  <!--border color,  location loop,  mono panner text,  range marker bar,  selection rect-->
     <Color name="neutral:background" value="202020ff"/>  <!--audio track base,  gtk_fg_tooltip,  processor control button: fil-->
-    <Color name="neutral:background2" value="555555ff"/>  <!--midi frame base,  recording waveform outline,  transport marker bar,  video timeline bar-->
+    <Color name="neutral:background2" value="555555ff"/>  <!--recording waveform outline,  transport marker bar,  video timeline bar-->
     <Color name="neutral:midground" value="7f7f7fff"/>  <!--grid line minor,  gtk_processor_fader_frame,  range drag bar rect,  ruler text-->
     <Color name="neutral:foreground2" value="ccccccff"/>  <!--marker track,  marker bar-->
     <Color name="neutral:foreground" value="e5e5e5ff"/>  <!--gtk_foreground,  arrange base,  gtk_texts,  -->
@@ -215,7 +215,6 @@
     <ColorAlias name="midi device: fill" alias="widget:bg"/>
     <ColorAlias name="midi device: fill active" alias="theme:bg"/>
     <ColorAlias name="midi device: led active" alias="alert:green"/>
-    <ColorAlias name="midi frame base" alias="neutral:background2"/>
     <ColorAlias name="midi input button: fill active" alias="widget:blue"/>
     <ColorAlias name="midi input button: led active" alias="widget:blue"/>
     <ColorAlias name="midi meter color0" alias="midi meter 52"/>
@@ -492,7 +491,6 @@
     <Modifier name="loop rectangle" modifier="= alpha:0.5"/>
     <Modifier name="marker bar" modifier="= alpha:0.5"/>
     <Modifier name="grid line" modifier="= alpha:1.0"/>
-    <Modifier name="midi frame base" modifier="= alpha:0.85"/>
     <Modifier name="midi note" modifier="= alpha:0.8"/>
     <Modifier name="midi note velocity text" modifier="= alpha:0.4666"/>
     <Modifier name="midi patch change fill" modifier="= alpha:0.6274"/>
diff --git a/gtk2_ardour/themes/dark-ardour.colors b/gtk2_ardour/themes/dark-ardour.colors
index d1c98107bd..b76e91e407 100644
--- a/gtk2_ardour/themes/dark-ardour.colors
+++ b/gtk2_ardour/themes/dark-ardour.colors
@@ -216,7 +216,6 @@
     <ColorAlias name="midi device: fill" alias="widget:bg"/>
     <ColorAlias name="midi device: fill active" alias="theme:bg"/>
     <ColorAlias name="midi device: led active" alias="alert:green"/>
-    <ColorAlias name="midi frame base" alias="neutral:background2"/>
     <ColorAlias name="midi input button: fill active" alias="alert:green"/>
     <ColorAlias name="midi input button: led active" alias="alert:red"/>
     <ColorAlias name="midi meter color0" alias="midi meter 52"/>
@@ -493,7 +492,6 @@
     <Modifier name="loop rectangle" modifier="= alpha:0.5"/>
     <Modifier name="marker bar" modifier="= alpha:0.5"/>
     <Modifier name="grid line" modifier="= alpha:1.0"/>
-    <Modifier name="midi frame base" modifier="= alpha:0.79"/>
     <Modifier name="midi note" modifier="= alpha:0.8"/>
     <Modifier name="midi note velocity text" modifier="= alpha:0.4666"/>
     <Modifier name="midi patch change fill" modifier="= alpha:0.6274"/>
diff --git a/gtk2_ardour/themes/diehard3-ardour.colors b/gtk2_ardour/themes/diehard3-ardour.colors
index 3e0e79e2e0..9aa9ab4cb6 100644
--- a/gtk2_ardour/themes/diehard3-ardour.colors
+++ b/gtk2_ardour/themes/diehard3-ardour.colors
@@ -216,7 +216,6 @@
     <ColorAlias name="midi device: fill" alias="widget:bg"/>
     <ColorAlias name="midi device: fill active" alias="theme:bg"/>
     <ColorAlias name="midi device: led active" alias="alert:green"/>
-    <ColorAlias name="midi frame base" alias="neutral:background2"/>
     <ColorAlias name="midi input button: fill active" alias="alert:green"/>
     <ColorAlias name="midi input button: led active" alias="alert:red"/>
     <ColorAlias name="midi meter color0" alias="midi meter 52"/>
@@ -493,7 +492,6 @@
     <Modifier name="inactive crossfade" modifier="= alpha:0.46660000000000001"/>
     <Modifier name="loop rectangle" modifier="= alpha:0.5"/>
     <Modifier name="marker bar" modifier="= alpha:0.5"/>
-    <Modifier name="midi frame base" modifier="= alpha:0.71474299065420555"/>
     <Modifier name="midi note" modifier="= alpha:0.82000000000000006"/>
     <Modifier name="midi note velocity text" modifier="= alpha:0.46660000000000001"/>
     <Modifier name="midi patch change fill" modifier="= alpha:0.62739999999999996"/>
diff --git a/gtk2_ardour/themes/recbox-ardour.colors b/gtk2_ardour/themes/recbox-ardour.colors
index a96bc07f77..8fdfcfc5f9 100644
--- a/gtk2_ardour/themes/recbox-ardour.colors
+++ b/gtk2_ardour/themes/recbox-ardour.colors
@@ -216,7 +216,6 @@
     <ColorAlias name="midi device: fill" alias="widget:bg"/>
     <ColorAlias name="midi device: fill active" alias="theme:bg"/>
     <ColorAlias name="midi device: led active" alias="alert:green"/>
-    <ColorAlias name="midi frame base" alias="neutral:background2"/>
     <ColorAlias name="midi input button: fill active" alias="alert:green"/>
     <ColorAlias name="midi input button: led active" alias="alert:red"/>
     <ColorAlias name="midi meter color0" alias="midi meter 52"/>
@@ -493,7 +492,6 @@
     <Modifier name="loop rectangle" modifier="= alpha:0.5"/>
     <Modifier name="marker bar" modifier="= alpha:0.5"/>
     <Modifier name="grid line" modifier="= alpha:1"/>
-    <Modifier name="midi frame base" modifier="= alpha:0.40000000000000002"/>
     <Modifier name="midi note" modifier="= alpha:0.80000000000000004"/>
     <Modifier name="midi note velocity text" modifier="= alpha:0.46660000000000001"/>
     <Modifier name="midi patch change fill" modifier="= alpha:0.62739999999999996"/>
diff --git a/gtk2_ardour/themes/unastudia-ardour.colors b/gtk2_ardour/themes/unastudia-ardour.colors
index f9eb9e9611..4fd114236b 100644
--- a/gtk2_ardour/themes/unastudia-ardour.colors
+++ b/gtk2_ardour/themes/unastudia-ardour.colors
@@ -214,7 +214,6 @@
     <ColorAlias name="midi device: fill" alias="widget:bg"/>
     <ColorAlias name="midi device: fill active" alias="theme:bg"/>
     <ColorAlias name="midi device: led active" alias="alert:blue"/>
-    <ColorAlias name="midi frame base" alias="neutral:background2"/>
     <ColorAlias name="midi input button: fill active" alias="alert:blue"/>
     <ColorAlias name="midi input button: led active" alias="alert:red"/>
     <ColorAlias name="midi meter color0" alias="midi meter 52"/>
@@ -491,7 +490,6 @@
     <Modifier name="loop rectangle" modifier="= alpha:0.5"/>
     <Modifier name="marker bar" modifier="= alpha:0.5"/>
     <Modifier name="grid line" modifier="= alpha:1.0"/>
-    <Modifier name="midi frame base" modifier="= alpha:0.85"/>
     <Modifier name="midi note" modifier="= alpha:0.8"/>
     <Modifier name="midi note velocity text" modifier="= alpha:0.4666"/>
     <Modifier name="midi patch change fill" modifier="= alpha:0.6274"/>
diff --git a/gtk2_ardour/themes/xcolors-ardour.colors b/gtk2_ardour/themes/xcolors-ardour.colors
index 5adfcb0ba3..b4434102d7 100644
--- a/gtk2_ardour/themes/xcolors-ardour.colors
+++ b/gtk2_ardour/themes/xcolors-ardour.colors
@@ -215,7 +215,6 @@
     <ColorAlias name="midi device: fill" alias="widget:bg"/>
     <ColorAlias name="midi device: fill active" alias="theme:bg"/>
     <ColorAlias name="midi device: led active" alias="alert:green"/>
-    <ColorAlias name="midi frame base" alias="neutral:background2"/>
     <ColorAlias name="midi input button: fill active" alias="alert:green"/>
     <ColorAlias name="midi input button: led active" alias="alert:red"/>
     <ColorAlias name="midi meter color0" alias="midi meter 52"/>
@@ -492,7 +491,6 @@
     <Modifier name="loop rectangle" modifier="= alpha:0.5"/>
     <Modifier name="marker bar" modifier="= alpha:0.5"/>
     <Modifier name="grid line" modifier="= alpha:0.8"/>
-    <Modifier name="midi frame base" modifier="= alpha:0.8"/>
     <Modifier name="midi note" modifier="= alpha:0.8"/>
     <Modifier name="midi note velocity text" modifier="= alpha:0.7"/>
     <Modifier name="midi patch change fill" modifier="= alpha:0.6"/>