Fixes #11561: Add float: left; to .form-control within input groups to prevent...

Fixes #11561: Add float: left; to .form-control within input groups to prevent IE9 from screwing up placeholder text and select menu arrows

dist/css/bootstrap.css

@@ -3208,6 +3208,7 @@ input[type="button"].btn-block {
   padding-left: 0;
 }
 .input-group .form-control {
+  float: left;
   width: 100%;
   margin-bottom: 0;
 }

less/input-groups.less

@@ -17,6 +17,11 @@
   }
 
   .form-control {
+    // IE9 fubars the placeholder attribute in text inputs and the arrows on
+    // select elements in input groups. To fix it, we float the input. Details:
+    // https://github.com/twbs/bootstrap/issues/11561#issuecomment-28936855
+    float: left;
+
     width: 100%;
     margin-bottom: 0;
   }