[build/scss]: Fix disabled style for some buttons.

build/scss/_buttons.scss

@@ -53,6 +53,13 @@
     background-color: darken($button-default-background-color, 5%);
     color: darken($button-default-color, 10%);
   }
+
+  &.disabled,
+  &:disabled {
+    color: $button-default-color;
+    background-color: $button-default-background-color;
+    border-color: $button-default-border-color;
+  }
 }
 
 // Application buttons

build/scss/mixins/_backgrounds.scss

@@ -37,8 +37,6 @@
     color: color-yiq($color);
 
     &.btn {
-      &.disabled,
-      &:disabled,
       &:not(:disabled):not(.disabled):active,
       &:not(:disabled):not(.disabled).active,
       .show > &.dropdown-toggle {
@@ -59,6 +57,13 @@
         border-color: darken($color, 12.5%);
         color: color-yiq(darken($color, 10%));
       }
+
+      &:disabled,
+      &.disabled {
+        background: $color linear-gradient(180deg, mix($body-bg, $color, 15%), $color) repeat-x !important;
+        background-image: none !important;
+        color: color-yiq($color);
+      }
     }
   }
 }