diff --git a/src/DevTools/DevTools.js b/src/DevTools/DevTools.js
index c78228e..84733f4 100644
--- a/src/DevTools/DevTools.js
+++ b/src/DevTools/DevTools.js
@@ -138,11 +138,15 @@ export default class DevTools extends util.Emitter
     }
     _setTransparency(opacity)
     {
+        if (!util.isNum(opacity)) return;
+
         this._opacity = opacity;
         if (this._isShow) this._$el.css({opacity});
     }
     _setDisplaySize(height)
     {
+        if (!util.isNum(height)) return;
+        
         this._$el.css({height: height + '%'});
     }
     _appendTpl()
diff --git a/src/Settings/Settings.scss b/src/Settings/Settings.scss
index 9e3a97f..fdaec70 100644
--- a/src/Settings/Settings.scss
+++ b/src/Settings/Settings.scss
@@ -61,6 +61,7 @@
                 position: relative;
                 top: -3px;
                 margin: 0 auto;
+                outline: none;
             }
             input::-webkit-slider-thumb {
                 -webkit-appearance: none;