--- a/toolkit/modules/SelectContentHelper.jsm
+++ b/toolkit/modules/SelectContentHelper.jsm
@@ -48,16 +48,17 @@ Object.defineProperty(SelectContentHelpe
 });
 
 this.SelectContentHelper.prototype = {
   init: function() {
     this.global.addMessageListener("Forms:SelectDropDownItem", this);
     this.global.addMessageListener("Forms:DismissedDropDown", this);
     this.global.addMessageListener("Forms:MouseOver", this);
     this.global.addMessageListener("Forms:MouseOut", this);
+    this.global.addMessageListener("Forms:MouseUp", this);
     this.global.addEventListener("pagehide", this);
     this.global.addEventListener("mozhidedropdown", this);
     let MutationObserver = this.element.ownerDocument.defaultView.MutationObserver;
     this.mut = new MutationObserver(mutations => {
       // Something changed the <select> while it was open, so
       // we'll poke a DeferredTask to update the parent sometime
       // in the very near future.
       this._updateTimer.arm();
@@ -66,16 +67,17 @@ this.SelectContentHelper.prototype = {
   },
 
   uninit: function() {
     this.element.openInParentProcess = false;
     this.global.removeMessageListener("Forms:SelectDropDownItem", this);
     this.global.removeMessageListener("Forms:DismissedDropDown", this);
     this.global.removeMessageListener("Forms:MouseOver", this);
     this.global.removeMessageListener("Forms:MouseOut", this);
+    this.global.removeMessageListener("Forms:MouseUp", this);
     this.global.removeEventListener("pagehide", this);
     this.global.removeEventListener("mozhidedropdown", this);
     this.element = null;
     this.global = null;
     this.mut.disconnect();
     this._updateTimer.disarm();
     this._updateTimer = null;
     gOpen = false;
@@ -167,16 +169,20 @@ this.SelectContentHelper.prototype = {
       case "Forms:MouseOver":
         DOMUtils.setContentState(this.element, kStateHover);
         break;
 
       case "Forms:MouseOut":
         DOMUtils.removeContentState(this.element, kStateHover);
         break;
 
+      case "Forms:MouseUp":
+        DOMUtils.removeContentState(this.element, kStateActive);
+        break;
+
     }
   },
 
   handleEvent: function(event) {
     switch (event.type) {
       case "pagehide":
         if (this.element.ownerDocument === event.target) {
           this.global.sendAsyncMessage("Forms:HideDropDown", {});

--- a/toolkit/modules/SelectParentHelper.jsm
+++ b/toolkit/modules/SelectParentHelper.jsm
@@ -63,16 +63,20 @@ this.SelectParentHelper = {
   hide: function(menulist, browser) {
     if (currentBrowser == browser) {
       menulist.menupopup.hidePopup();
     }
   },
 
   handleEvent: function(event) {
     switch (event.type) {
+      case "mouseup":
+        currentBrowser.messageManager.sendAsyncMessage("Forms:MouseUp", {});
+        break;
+
       case "mouseover":
         currentBrowser.messageManager.sendAsyncMessage("Forms:MouseOver", {});
         break;
 
       case "mouseout":
         currentBrowser.messageManager.sendAsyncMessage("Forms:MouseOut", {});
         break;
 
@@ -125,26 +129,28 @@ this.SelectParentHelper = {
     }
   },
 
   _registerListeners: function(browser, popup) {
     popup.addEventListener("command", this);
     popup.addEventListener("popuphidden", this);
     popup.addEventListener("mouseover", this);
     popup.addEventListener("mouseout", this);
+    browser.ownerDocument.defaultView.addEventListener("mouseup", this, true);
     browser.ownerDocument.defaultView.addEventListener("keydown", this, true);
     browser.ownerDocument.defaultView.addEventListener("fullscreen", this, true);
     browser.messageManager.addMessageListener("Forms:UpdateDropDown", this);
   },
 
   _unregisterListeners: function(browser, popup) {
     popup.removeEventListener("command", this);
     popup.removeEventListener("popuphidden", this);
     popup.removeEventListener("mouseover", this);
     popup.removeEventListener("mouseout", this);
+    browser.ownerDocument.defaultView.removeEventListener("mouseup", this, true);
     browser.ownerDocument.defaultView.removeEventListener("keydown", this, true);
     browser.ownerDocument.defaultView.removeEventListener("fullscreen", this, true);
     browser.messageManager.removeMessageListener("Forms:UpdateDropDown", this);
   },
 
 };
 
 function populateChildren(menulist, options, selectedIndex, zoom,