1 files changed, 31 insertions, 10 deletions
diff --git a/less/dropdowns.less b/less/dropdowns.less
index 5d7e0fb4e..dde2038e3 100644
--- a/less/dropdowns.less
+++ b/less/dropdowns.less
@@ -10,12 +10,9 @@
   height: 0;
   margin-left: 2px;
   vertical-align: middle;
-  border-top:   @caret-width-base solid @dropdown-caret-color;
+  border-top:   @caret-width-base solid;
   border-right: @caret-width-base solid transparent;
   border-left:  @caret-width-base solid transparent;
-  // Firefox fix for https://github.com/twbs/bootstrap/issues/9538. Once fixed,
-  // we can just straight up remove this.
-  border-bottom: 0 dotted;
 }
 
 // The dropdown wrapper (div)
@@ -49,6 +46,8 @@
   background-clip: padding-box;
 
   // Aligns the dropdown menu to right
+  //
+  // Deprecated as of 3.1 in favor of `.dropdown-menu-[dir]`
   &.pull-right {
     right: 0;
     left: auto;
@@ -129,6 +128,25 @@
   }
 }
 
+// Menu positioning
+//
+// Add extra class to `.dropdown-menu` to flip the alignment of the dropdown
+// menu with the parent.
+.dropdown-menu-right {
+  left: auto; // Reset the default from `.dropdown-menu`
+  right: 0;
+}
+// With v3, we enabled auto-flipping if you have a dropdown within a right
+// aligned nav component. To enable the undoing of that, we provide an override
+// to restore the default dropdown menu alignment.
+//
+// This is only for left-aligning a dropdown menu within a `.navbar-right` or
+// `.pull-right` nav component.
+.dropdown-menu-left {
+  left: 0;
+  right: auto;
+}
+
 // Dropdown section headers
 .dropdown-header {
   display: block;
@@ -145,7 +163,7 @@
   right: 0;
   bottom: 0;
   top: 0;
-  z-index: @zindex-dropdown - 10;
+  z-index: (@zindex-dropdown - 10);
 }
 
 // Right aligned dropdowns
@@ -163,10 +181,8 @@
 .navbar-fixed-bottom .dropdown {
   // Reverse the caret
   .caret {
-    // Firefox fix for https://github.com/twbs/bootstrap/issues/9538. Once this
-    // gets fixed, restore `border-top: 0;`.
-    border-top: 0 dotted;
-    border-bottom: @caret-width-base solid @dropdown-caret-color;
+    border-top: 0;
+    border-bottom: @caret-width-base solid;
     content: "";
   }
   // Different positioning for bottom up menu
@@ -185,7 +201,12 @@
 @media (min-width: @grid-float-breakpoint) {
   .navbar-right {
     .dropdown-menu {
-      .pull-right > .dropdown-menu();
+      .dropdown-menu-right();
+    }
+    // Necessary for overrides of the default right aligned menu.
+    // Will remove come v4 in all likelihood.
+    .dropdown-menu-left {
+      .dropdown-menu-left();
     }
   }
 }