restore IE filters, but reset them on buttons

docs/assets/css/bootstrap.css

@@ -1911,6 +1911,7 @@ table .span12 {
   background-image: -o-linear-gradient(top, #333333, #222222);
   background-image: linear-gradient(top, #333333, #222222);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#333333', endColorstr='#222222', GradientType=0);
   -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.25), inset 0 -1px 0 rgba(0, 0, 0, 0.1);
   -moz-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.25), inset 0 -1px 0 rgba(0, 0, 0, 0.1);
   box-shadow: 0 1px 3px rgba(0, 0, 0, 0.25), inset 0 -1px 0 rgba(0, 0, 0, 0.1);
@@ -2125,6 +2126,7 @@ table .span12 {
   background-image: -o-linear-gradient(top, #ffffff, #f5f5f5);
   background-image: linear-gradient(top, #ffffff, #f5f5f5);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#f5f5f5', GradientType=0);
   border: 1px solid #ddd;
   -webkit-border-radius: 3px;
   -moz-border-radius: 3px;
@@ -2524,8 +2526,10 @@ table .span12 {
   background-image: -o-linear-gradient(top, #0088cc, #0044cc);
   background-image: linear-gradient(top, #0088cc, #0044cc);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#0088cc', endColorstr='#0044cc', GradientType=0);
   border-color: #0044cc #0044cc #002a80;
   border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
+  filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
 }
 .btn.primary:hover,
 .btn.primary:active,
@@ -2546,8 +2550,10 @@ table .span12 {
   background-image: -o-linear-gradient(top, #ee5f5b, #bd362f);
   background-image: linear-gradient(top, #ee5f5b, #bd362f);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ee5f5b', endColorstr='#bd362f', GradientType=0);
   border-color: #bd362f #bd362f #802420;
   border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
+  filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
 }
 .btn.danger:hover,
 .btn.danger:active,
@@ -2568,8 +2574,10 @@ table .span12 {
   background-image: -o-linear-gradient(top, #62c462, #51a351);
   background-image: linear-gradient(top, #62c462, #51a351);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#62c462', endColorstr='#51a351', GradientType=0);
   border-color: #51a351 #51a351 #387038;
   border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
+  filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
 }
 .btn.success:hover,
 .btn.success:active,
@@ -2590,8 +2598,10 @@ table .span12 {
   background-image: -o-linear-gradient(top, #5bc0de, #2f96b4);
   background-image: linear-gradient(top, #5bc0de, #2f96b4);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#5bc0de', endColorstr='#2f96b4', GradientType=0);
   border-color: #2f96b4 #2f96b4 #1f6377;
   border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
+  filter: progid:DXImageTransform.Microsoft.gradient(enabled = false);
 }
 .btn.info:hover,
 .btn.info:active,
@@ -2619,6 +2629,7 @@ table .span12 {
   background-image: -o-linear-gradient(#ffffff, #ffffff 25%, #e6e6e6);
   background-image: linear-gradient(#ffffff, #ffffff 25%, #e6e6e6);
   background-repeat: no-repeat;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#e6e6e6', GradientType=0);
   border: 1px solid #ccc;
   border-bottom-color: #bbb;
   -webkit-border-radius: 4px;
@@ -2980,6 +2991,7 @@ a.thumbnail:hover {
   background-image: -o-linear-gradient(top, #f5f5f5, #f9f9f9);
   background-image: linear-gradient(top, #f5f5f5, #f9f9f9);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#f5f5f5', endColorstr='#f9f9f9', GradientType=0);
   -webkit-box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
   -moz-box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
   box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
@@ -3002,6 +3014,7 @@ a.thumbnail:hover {
   background-image: -o-linear-gradient(top, #149bdf, #0480be);
   background-image: linear-gradient(top, #149bdf, #0480be);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#149bdf', endColorstr='#0480be', GradientType=0);
   -webkit-box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.15);
   -moz-box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.15);
   box-shadow: inset 0 -1px 0 rgba(0, 0, 0, 0.15);
@@ -3041,6 +3054,7 @@ a.thumbnail:hover {
   background-image: -o-linear-gradient(top, #ee5f5b, #c43c35);
   background-image: linear-gradient(top, #ee5f5b, #c43c35);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ee5f5b', endColorstr='#c43c35', GradientType=0);
 }
 .progress.danger.striped .bar {
   background-color: #ee5f5b;
@@ -3060,6 +3074,7 @@ a.thumbnail:hover {
   background-image: -o-linear-gradient(top, #62c462, #57a957);
   background-image: linear-gradient(top, #62c462, #57a957);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#62c462', endColorstr='#57a957', GradientType=0);
 }
 .progress.success.striped .bar {
   background-color: #62c462;
@@ -3079,6 +3094,7 @@ a.thumbnail:hover {
   background-image: -o-linear-gradient(top, #5bc0de, #339bb9);
   background-image: linear-gradient(top, #5bc0de, #339bb9);
   background-repeat: repeat-x;
+  filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#5bc0de', endColorstr='#339bb9', GradientType=0);
 }
 .progress.info.striped .bar {
   background-color: #5bc0de;

less/mixins.less

@@ -298,6 +298,7 @@
     background-image: -o-linear-gradient(left, @startColor, @endColor); // Opera 11.10
     background-image: linear-gradient(left, @startColor, @endColor); // Le standard
     background-repeat: repeat-x;
+    filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=1)",@startColor,@endColor)); // IE9 and down
   }
   .vertical(@startColor: #555, @endColor: #333) {
     background-color: mix(@startColor, @endColor, 60%);
@@ -308,6 +309,7 @@
     background-image: -o-linear-gradient(top, @startColor, @endColor); // Opera 11.10
     background-image: linear-gradient(top, @startColor, @endColor); // The standard
     background-repeat: repeat-x;
+    filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=0)",@startColor,@endColor)); // IE9 and down
   }
   .directional(@startColor: #555, @endColor: #333, @deg: 45deg) {
     background-color: @endColor;
@@ -327,6 +329,7 @@
     background-image: -o-linear-gradient(@startColor, @midColor @colorStop, @endColor);
     background-image: linear-gradient(@startColor, @midColor @colorStop, @endColor);
     background-repeat: no-repeat;
+    filter: e(%("progid:DXImageTransform.Microsoft.gradient(startColorstr='%d', endColorstr='%d', GradientType=0)",@startColor,@endColor)); // IE9 and down, gets no color-stop at all for proper fallback
   }
   .radial(@innerColor: #555, @outerColor: #333)  {
     background-color: @outerColor;
@@ -347,6 +350,10 @@
     background-image: linear-gradient(@angle, rgba(255,255,255,.15) 25%, transparent 25%, transparent 50%, rgba(255,255,255,.15) 50%, rgba(255,255,255,.15) 75%, transparent 75%, transparent);
   }
 }
+// Reset filters for IE
+.reset-filter() {
+  filter: e(%("progid:DXImageTransform.Microsoft.gradient(enabled = false)"));
+}
 
 
 // Mixin for generating button backgrounds
@@ -354,6 +361,7 @@
 .buttonBackground(@startColor, @endColor) {
   // gradientBar will set the background to a pleasing blend of these, to support IE<=9
   .gradientBar(@startColor, @endColor);
+  .reset-filter();
 
   // in these cases the gradient won't cover the background, so we override
   &:hover, &:active, &.active, &.disabled, &[disabled] {