app/frameworks/twitter/bootstrap/button-groups.less in bootstrap_farsi-3.2.0.1 vs app/frameworks/twitter/bootstrap/button-groups.less in bootstrap_farsi-3.3.6

@@ -16,14 +16,10 @@
     &:focus,
     &:active,
     &.active {
       z-index: 2;
     }
-    &:focus {
-      // Remove focus outline when dropdown JS adds it after closing the menu
-      outline: 0;
-    }
   }
 }
 
 // Prevent double borders when buttons are next to each other
 .btn-group {
@@ -38,10 +34,11 @@
 // Optional: Group multiple button groups together for a toolbar
 .btn-toolbar {
   .margin-left(-5px); // Offset the first child's margin
   &:extend(.clearfix all);
 
+  .btn,
   .btn-group,
   .input-group {
     .float(left);
   }
   > .btn,
@@ -73,17 +70,17 @@
   .float(left);
 }
 .btn-group > .btn-group:not(:first-child):not(:last-child) > .btn {
   border-radius: 0;
 }
-.btn-group > .btn-group:first-child {
+.btn-group > .btn-group:first-child:not(:last-child) {
   > .btn:last-child,
   > .dropdown-toggle {
     .border-right-radius(0);
   }
 }
-.btn-group > .btn-group:last-child > .btn:first-child {
+.btn-group > .btn-group:last-child:not(:first-child) > .btn:first-child {
   .border-left-radius(0);
 }
 
 // On active and open, don't show outline
 .btn-group .dropdown-toggle:active,
@@ -174,16 +171,16 @@
 .btn-group-vertical > .btn {
   &:not(:first-child):not(:last-child) {
     border-radius: 0;
   }
   &:first-child:not(:last-child) {
-    .border-top-right-radius(@border-radius-base);
+    .border-top-radius(@btn-border-radius-base);
     .border-bottom-radius(0);
   }
   &:last-child:not(:first-child) {
-    .border-bottom-left-radius(@border-radius-base);
     .border-top-radius(0);
+    .border-bottom-radius(@btn-border-radius-base);
   }
 }
 .btn-group-vertical > .btn-group:not(:first-child):not(:last-child) > .btn {
   border-radius: 0;
 }
@@ -196,11 +193,10 @@
 .btn-group-vertical > .btn-group:last-child:not(:first-child) > .btn:first-child {
   .border-top-radius(0);
 }
 
 
-
 // Justified button groups
 // ----------------------
 
 .btn-group-justified {
   display: table;
@@ -224,17 +220,25 @@
 
 
 // Checkbox and radio options
 //
 // In order to support the browser's form validation feedback, powered by the
-// `required` attribute, we have to "hide" the inputs via `opacity`. We cannot
-// use `display: none;` or `visibility: hidden;` as that also hides the popover.
+// `required` attribute, we have to "hide" the inputs via `clip`. We cannot use
+// `display: none;` or `visibility: hidden;` as that also hides the popover.
+// Simply visually hiding the inputs via `opacity` would leave them clickable in
+// certain cases which is prevented by using `clip` and `pointer-events`.
 // This way, we ensure a DOM element is visible to position the popover from.
 //
-// See https://github.com/twbs/bootstrap/pull/12794 for more.
+// See https://github.com/twbs/bootstrap/pull/12794 and
+// https://github.com/twbs/bootstrap/pull/14559 for more information.
 
-[data-toggle="buttons"] > .btn > input[type="radio"],
-[data-toggle="buttons"] > .btn > input[type="checkbox"] {
-  position: absolute;
-  z-index: -1;
-  .opacity(0);
+[data-toggle="buttons"] {
+  > .btn,
+  > .btn-group > .btn {
+    input[type="radio"],
+    input[type="checkbox"] {
+      position: absolute;
+      clip: rect(0,0,0,0);
+      pointer-events: none;
+    }
+  }
 }