fix: Make sure drop indicator is under the last item when newtab button is below, b=no-bug, c=common

Author: mr-cheffy

src/zen/common/modules/ZenUIManager.mjs

@@ -891,8 +891,8 @@ window.gZenVerticalTabsManager = {
             marginBottom: isLastItem() ? ["0px", "0px"] : [transform, "0px"],
           },
           {
-            duration: 0.11,
-            easing: "ease-out",
+            duration: 0.075,
+            easing: "easeOut",
           }
         )
         .then(() => {})
@@ -913,8 +913,8 @@ window.gZenVerticalTabsManager = {
             filter: ["blur(1px)", "blur(0px)"],
           },
           {
-            duration: 0.11,
-            easing: "ease-out",
+            duration: 0.075,
+            easing: "easeOut",
           }
         )
         .then(() => {})
@@ -949,7 +949,7 @@ window.gZenVerticalTabsManager = {
       },
       {
         duration: 0.075,
-        easing: "ease-out",
+        easing: "easeOut",
       }
     );
   },

src/zen/drag-and-drop/ZenDragAndDrop.js

@@ -931,7 +931,7 @@
         if (event.target.classList.contains("zen-workspace-empty-space") || hoveringPeriphery) {
           let lastTab = gBrowser.tabs.at(-1);
           dropElement =
-            (hoveringPeriphery
+            (hoveringPeriphery && Services.prefs.getBoolPref("zen.view.show-newtab-button-top")
               ? this._tabbrowserTabs.ariaFocusableItems.at(
                   gBrowser._numVisiblePinTabsWithoutCollapsed
                 )