diff --git a/browser/components/tabbrowser/content/tabbrowser.js b/browser/components/tabbrowser/content/tabbrowser.js
index c89ae2cbb978d6218bd56a059c5ca1e371231607..6608e0d7df1092a7398979abb166895e0b4fb66b 100644
--- a/browser/components/tabbrowser/content/tabbrowser.js
+++ b/browser/components/tabbrowser/content/tabbrowser.js
@@ -456,11 +456,26 @@
       return duplicateTabs;
     },
 
+    get _numVisiblePinTabs() {
+      let i = 0;
+      for (let tab of this.tabs) {
+        if (!tab.pinned) {
+          break;
+        }
+        if (!tab.hidden) {
+          i++;
+        }
+      }
+      return i;
+    },
+
     get _numPinnedTabs() {
-      for (var i = 0; i < this.tabs.length; i++) {
-        if (!this.tabs[i].pinned) {
+      let i = 0;
+      for (let tab of this.tabs) {
+        if (!tab.pinned) {
           break;
         }
+        i++;
       }
       return i;
     },
@@ -2705,6 +2720,11 @@
         );
       }
 
+      let hasZenDefaultUserContextId = false;
+      if (typeof ZenWorkspaces !== "undefined") {
+        [userContextId, hasZenDefaultUserContextId] = ZenWorkspaces.getContextIdIfNeeded(userContextId);
+      }
+
       if (!UserInteraction.running("browser.tabs.opening", window)) {
         UserInteraction.start("browser.tabs.opening", "initting", window);
       }
@@ -2773,6 +2793,9 @@
           noInitialLabel,
           skipBackgroundNotify,
         });
+        if (hasZenDefaultUserContextId) {
+          t.setAttribute("zenDefaultUserContextId", "true");
+        }
         if (insertTab) {
           // insert the tab into the tab container in the correct position
           this._insertTabAtIndex(t, {
@@ -3262,6 +3285,14 @@
         ) {
           tabWasReused = true;
           tab = this.selectedTab;
+
+          if (tabData.zenWorkspace) {
+            tab.setAttribute("zen-workspace-id", tabData.zenWorkspace);
+          }
+          if (tabData.zenDefaultUserContextId) {
+            tab.setAttribute("zenDefaultUserContextId", "true");
+          }
+
           if (!tabData.pinned) {
             this.unpinTab(tab);
           } else {
@@ -3283,6 +3314,13 @@
             url = tabData.entries[activeIndex].url;
           }
 
+          if(Services.prefs.getBoolPref("zen.pinned-tab-manager.restore-pinned-tabs-to-pinned-url", false) && tabData.pinned && tabData.zenPinnedUrl) {
+            tabData.entries = [{url: tabData.zenPinnedUrl, title: tabData.zenPinnedTitle}];
+            tabData.image = tabData.zenPinnedIcon;
+            tabData.index = 0;
+            url = tabData.zenPinnedUrl;
+          }
+
           let preferredRemoteType = E10SUtils.getRemoteTypeForURI(
             url,
             gMultiProcessBrowser,
@@ -3311,6 +3349,12 @@
             preferredRemoteType,
           });
 
+          if (tabData.zenWorkspace) {
+            tab.setAttribute("zen-workspace-id", tabData.zenWorkspace);
+          }
+          if (tabData.zenDefaultUserContextId) {
+            tab.setAttribute("zenDefaultUserContextId", "true");
+          }
           if (select) {
             tabToSelect = tab;
           }
@@ -3345,7 +3389,17 @@
             this.tabContainer._invalidateCachedTabs();
           }
         }
+        if (tabData.zenPinnedUrl) {
+          tab.setAttribute("zen-pinned-url", tabData.zenPinnedUrl);
+        }
 
+        if (tabData.zenPinnedTitle) {
+          tab.setAttribute("zen-pinned-title", tabData.zenPinnedTitle);
+        }
+
+        if(tabData.zenPinnedIcon) {
+          tab.setAttribute("zen-pinned-icon", tabData.zenPinnedIcon);
+        }
         tab.initialize();
       }
 
@@ -4198,6 +4252,7 @@
         isLastTab ||
         aTab.pinned ||
         aTab.hidden ||
+        true ||
         this._removingTabs.size >
           3 /* don't want lots of concurrent animations */ ||
         !aTab.hasAttribute(
@@ -5131,10 +5186,10 @@
       SessionStore.deleteCustomTabValue(aTab, "hiddenBy");
     },
 
-    hideTab(aTab, aSource) {
+    hideTab(aTab, aSource, forZenWorkspaces = false) {
       if (
         aTab.hidden ||
-        aTab.pinned ||
+        (aTab.pinned && !forZenWorkspaces) ||
         aTab.selected ||
         aTab.closing ||
         // Tabs that are sharing the screen, microphone or camera cannot be hidden.
@@ -7870,7 +7925,14 @@ var TabContextMenu = {
     );
     contextUnpinSelectedTabs.hidden =
       !this.contextTab.pinned || !multiselectionContext;
-
+    let contextResetPinnedTab = document.getElementById("context_zen-reset-pinned-tab");
+    if(contextResetPinnedTab) {
+      contextResetPinnedTab.hidden = !this.contextTab.pinned || !this.contextTab.getAttribute("zen-pinned-url") || multiselectionContext;
+    }
+    let contextReplacePinnedUrlWithCurrent = document.getElementById("context_zen-replace-pinned-url-with-current");
+    if(contextReplacePinnedUrlWithCurrent) {
+      contextReplacePinnedUrlWithCurrent.hidden = !this.contextTab.pinned || !this.contextTab.getAttribute("zen-pinned-url") || multiselectionContext;
+    }
     // Move Tab items
     let contextMoveTabOptions = document.getElementById(
       "context_moveTabOptions"