combined .disabled and [disabled] and confirmed in ie7/8

less/buttons.less

@@ -82,16 +82,8 @@
     background-color: darken(@white, 10%);
     background-color: darken(@white, 15%) e("\9");
   }
-  &.disabled {
-    cursor: default;
-    background-image: none;
-    background-color: darken(@white, 10%);
-    .opacity(65);
-    .box-shadow(none);
-  }
+  &.disabled,
   &[disabled] {
-    // disabled pseudo can't be included with .disabled
-    // def because IE8 and below will drop it ;_;
     cursor: default;
     background-image: none;
     background-color: darken(@white, 10%);

less/mixins.less

@@ -360,12 +360,7 @@
   .gradientBar(@startColor, @endColor);
 
   // in these cases the gradient won't cover the background, so we override
-  &:hover, &:active, &.active, &.disabled {
-    background-color: @endColor;
-  }
-
-  // called out separately because IE8 would ignore otherwise
-  &[disabled] {
+  &:hover, &:active, &.active, &.disabled, &[disabled] {
     background-color: @endColor;
   }