diff --git a/Ooui.Forms/VisualElementTracker.cs b/Ooui.Forms/VisualElementTracker.cs
index 18a5cc9..ab65c78 100644
--- a/Ooui.Forms/VisualElementTracker.cs
+++ b/Ooui.Forms/VisualElementTracker.cs
@@ -149,7 +149,12 @@ namespace Ooui.Forms
             else if (width <= 0 || height <= 0) {
                 return;
             }
-            uiview.Style.Opacity = opacity;
+            if (opacity >= 1.0f) {
+                uiview.Style.Opacity = null;
+            }
+            else {
+                uiview.Style.Opacity = opacity;
+            }
 
             //var transform = 0;
             //const double epsilon = 0.001;
diff --git a/Ooui/Style.cs b/Ooui/Style.cs
index 0a8cb08..a92f6d3 100644
--- a/Ooui/Style.cs
+++ b/Ooui/Style.cs
@@ -338,7 +338,8 @@ namespace Ooui
                 var safeValue = value ?? "inherit";
                 lock (properties) {
                     if (value == null) {
-                        properties.Remove (propertyName);
+                        if (!properties.Remove (propertyName))
+                            return;
                     }
                     else {
                         Value old;