diff --git a/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/Animation.java b/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/Animation.java
index a358e47e5..18036a2fc 100644
--- a/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/Animation.java
+++ b/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/Animation.java
@@ -562,8 +562,10 @@ public class Animation {
 						break;
 					case first:
 					case replace:
-						bone.scaleX += (x - bone.scaleX * Math.signum(x)) * alpha;
-						bone.scaleY += (y - bone.scaleY * Math.signum(y)) * alpha;
+						bx = Math.abs(bone.scaleX) * Math.signum(x);
+						by = Math.abs(bone.scaleY) * Math.signum(y);
+						bone.scaleX = bx + (x - bx) * alpha;
+						bone.scaleY = by + (y - by) * alpha;
 						break;
 					case add:
 						bx = Math.signum(x);
diff --git a/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/AnimationState.java b/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/AnimationState.java
index 93e866b1a..84e4c5cb0 100644
--- a/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/AnimationState.java
+++ b/spine-libgdx/spine-libgdx/src/com/esotericsoftware/spine/AnimationState.java
@@ -658,7 +658,7 @@ public class AnimationState {
 
 		for (int i = 0, n = tracks.size; i < n; i++) {
 			TrackEntry entry = tracks.get(i);
-			if (entry != null && entry.mixBlend != MixBlend.add) entry.setTimelineData(null, mixingTo, propertyIDs);
+			if (entry != null && (i == 0 || entry.mixBlend != MixBlend.add)) entry.setTimelineData(null, mixingTo, propertyIDs);
 		}
 	}
 
diff --git a/spine-libgdx/spine-skeletonviewer/src/com/esotericsoftware/spine/SkeletonViewer.java b/spine-libgdx/spine-skeletonviewer/src/com/esotericsoftware/spine/SkeletonViewer.java
index 1bd2cfbbf..37a3f34d5 100644
--- a/spine-libgdx/spine-skeletonviewer/src/com/esotericsoftware/spine/SkeletonViewer.java
+++ b/spine-libgdx/spine-skeletonviewer/src/com/esotericsoftware/spine/SkeletonViewer.java
@@ -496,6 +496,8 @@ public class SkeletonViewer extends ApplicationAdapter {
 
 			alphaSlider.setValue(1);
 			alphaSlider.setDisabled(true);
+			
+			addCheckbox.setDisabled(true);
 
 			window.setMovable(false);
 			window.setResizable(false);