Worked a bit more on split view groups

src/browser/base/content/zen-styles/zen-folders.css

@@ -37,6 +37,12 @@ tab-group[split-view-group] {
   & .tab-close-button {
     display: none !important;
   }
+
+  @media (prefers-reduced-motion: no-preference) {
+    #tabbrowser-tabs[movingtab] & {
+      transition: var(--tab-dragover-transition);
+    }
+  }
 }
 
 tab-group[split-view-group] .tabbrowser-tab {

src/browser/base/zen-components/ZenFolders.mjs

@@ -19,6 +19,12 @@
     #onTabUngrouped(event) {}
 
     #onTabGroupRemoved(event) {}
+
+    expandGroupTabs(group) {
+      for (const tab of group.tabs) {
+        gBrowser.ungroupTab(tab);
+      }
+    }
   }
 
   window.gZenFolders = new ZenFolders();

src/browser/base/zen-components/ZenViewSplitter.mjs

@@ -565,6 +565,8 @@ class ZenViewSplitter extends ZenDOMOperatedFeature {
    * @param {number} groupIndex - The index of the group to remove.
    */
   removeGroup(groupIndex) {
+    const group = this._data[groupIndex];
+    gZenFolders.expandGroupTabs(group);
     if (this.currentView === groupIndex) {
       this.deactivateCurrentSplitView();
     }
@@ -721,7 +723,7 @@ class ZenViewSplitter extends ZenDOMOperatedFeature {
       } else {
         // Add any tabs that are not already in the group
         for (const tab of tabs) {
-          if (!group.tabs.includes(tab)) {
+          if (!group.tabs.includes(tab) && tab.pinned === group.pinned) { 
             group.tabs.push(tab);
             this.addTabToSplit(tab, group.layoutTree);
           }

src/browser/components/tabbrowser/content/tabbrowser-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/components/tabbrowser/content/tabbrowser.js b/browser/components/tabbrowser/content/tabbrowser.js
-index 628aa6596627c85efe361fc1ece8fd58f7ee653e..59c563683fc18972fffd51c41d1d1c159b62f28d 100644
+index 628aa6596627c85efe361fc1ece8fd58f7ee653e..a1500038ff8f129fc249a221c2b534c8b2edf053 100644
 --- a/browser/components/tabbrowser/content/tabbrowser.js
 +++ b/browser/components/tabbrowser/content/tabbrowser.js
 @@ -412,11 +412,50 @@
@@ -441,21 +441,28 @@ index 628aa6596627c85efe361fc1ece8fd58f7ee653e..59c563683fc18972fffd51c41d1d1c15
        } else {
          aIndex = Math.max(aIndex, this.pinnedTabCount);
        }
-@@ -5684,9 +5797,11 @@
+@@ -5684,11 +5797,17 @@
        }
  
        this._handleTabMove(aTab, () => {
 -        let neighbor = this.tabs[aIndex];
 -        if (forceStandaloneTab && neighbor.group) {
 +        let neighbor = this.tabs.filter(tab => !tab.hasAttribute("zen-glance-tab"))[aIndex];
-+        if (forceStandaloneTab && neighbor.group || (neighbor.group && neighbor.group.hasAttribute("split-view-group"))) {
++        const _tPos = aTab._tPos;
++        if ((forceStandaloneTab && neighbor.group) || neighbor.group?.hasAttribute("split-view-group")) {
            neighbor = neighbor.group;
 +        } else if (aTab.group && aTab.group.hasAttribute("split-view-group")) {
 +          aTab = aTab.group;
++        }
++        if (aTab.group?.hasAttribute("split-view-group") && neighbor == aTab.group) {
++          return;
          }
-         if (neighbor && aIndex >= aTab._tPos) {
+-        if (neighbor && aIndex >= aTab._tPos) {
++        if (neighbor && aIndex >= _tPos) {
            neighbor.after(aTab);
-@@ -5697,7 +5812,7 @@
+         } else {
+           this.tabContainer.insertBefore(aTab, neighbor);
+@@ -5697,7 +5816,7 @@
      }
  
      moveTabToGroup(aTab, aGroup) {
@@ -464,7 +471,7 @@ index 628aa6596627c85efe361fc1ece8fd58f7ee653e..59c563683fc18972fffd51c41d1d1c15
          return;
        }
        if (aTab.group && aTab.group.id === aGroup.id) {
-@@ -5721,6 +5836,8 @@
+@@ -5721,6 +5840,8 @@
  
        moveActionCallback();
  
@@ -473,7 +480,7 @@ index 628aa6596627c85efe361fc1ece8fd58f7ee653e..59c563683fc18972fffd51c41d1d1c15
        // Clear tabs cache after moving nodes because the order of tabs may have
        // changed.
        this.tabContainer._invalidateCachedTabs();
-@@ -5771,7 +5888,7 @@
+@@ -5771,7 +5892,7 @@
          createLazyBrowser,
        };
  
@@ -482,7 +489,7 @@ index 628aa6596627c85efe361fc1ece8fd58f7ee653e..59c563683fc18972fffd51c41d1d1c15
        if (aIndex < numPinned || (aTab.pinned && aIndex == numPinned)) {
          params.pinned = true;
        }
-@@ -7415,6 +7532,7 @@
+@@ -7415,6 +7536,7 @@
              aWebProgress.isTopLevel
            ) {
              this.mTab.setAttribute("busy", "true");
@@ -490,7 +497,7 @@ index 628aa6596627c85efe361fc1ece8fd58f7ee653e..59c563683fc18972fffd51c41d1d1c15
              gBrowser._tabAttrModified(this.mTab, ["busy"]);
              this.mTab._notselectedsinceload = !this.mTab.selected;
            }
-@@ -8381,7 +8499,7 @@ var TabContextMenu = {
+@@ -8381,7 +8503,7 @@ var TabContextMenu = {
      );
      contextUnpinSelectedTabs.hidden =
        !this.contextTab.pinned || !multiselectionContext;
@@ -499,7 +506,7 @@ index 628aa6596627c85efe361fc1ece8fd58f7ee653e..59c563683fc18972fffd51c41d1d1c15
      // Move Tab items
      let contextMoveTabOptions = document.getElementById(
        "context_moveTabOptions"
-@@ -8414,7 +8532,7 @@ var TabContextMenu = {
+@@ -8414,7 +8536,7 @@ var TabContextMenu = {
      let contextMoveTabToStart = document.getElementById("context_moveToStart");
      let isFirstTab =
        tabsToMove[0] == visibleTabs[0] ||
@@ -508,7 +515,7 @@ index 628aa6596627c85efe361fc1ece8fd58f7ee653e..59c563683fc18972fffd51c41d1d1c15
      contextMoveTabToStart.disabled = isFirstTab && allSelectedTabsAdjacent;
  
      document.getElementById("context_openTabInWindow").disabled =
-@@ -8647,6 +8765,7 @@ var TabContextMenu = {
+@@ -8647,6 +8769,7 @@ var TabContextMenu = {
      if (this.contextTab.multiselected) {
        gBrowser.removeMultiSelectedTabs();
      } else {

src/browser/components/tabbrowser/content/tabs-js.patch

@@ -1,5 +1,5 @@
 diff --git a/browser/components/tabbrowser/content/tabs.js b/browser/components/tabbrowser/content/tabs.js
-index fa96568d366fd3608f9bd583fa793150bd815c8b..2ef63a6b462f28029f02decf14ad93de88446bab 100644
+index fa96568d366fd3608f9bd583fa793150bd815c8b..03a525205457f723e204614834e32e7a917f41f7 100644
 --- a/browser/components/tabbrowser/content/tabs.js
 +++ b/browser/components/tabbrowser/content/tabs.js
 @@ -94,7 +94,7 @@
@@ -328,15 +328,16 @@ index fa96568d366fd3608f9bd583fa793150bd815c8b..2ef63a6b462f28029f02decf14ad93de
        let absPositionHorizontalTabs =
          this.overflowing && tabs.length > numPinned && numPinned > 0;
  
-@@ -2042,6 +2078,7 @@
+@@ -2041,7 +2077,7 @@
+ 
        if (this.verticalMode) {
          this._updateVerticalPinnedTabs();
-       } else if (absPositionHorizontalTabs) {
+-      } else if (absPositionHorizontalTabs) {
-+        return;
++      } else if (absPositionHorizontalTabs && false) {
          let layoutData = this._pinnedTabsLayoutCache;
          let uiDensity = document.documentElement.getAttribute("uidensity");
          if (!layoutData || layoutData.uiDensity != uiDensity) {
-@@ -2113,7 +2150,7 @@
+@@ -2113,7 +2149,7 @@
          return;
        }
  
@@ -345,7 +346,7 @@ index fa96568d366fd3608f9bd583fa793150bd815c8b..2ef63a6b462f28029f02decf14ad93de
  
        let directionX = screenX > dragData.animLastScreenX;
        let directionY = screenY > dragData.animLastScreenY;
-@@ -2296,10 +2333,11 @@
+@@ -2296,10 +2332,11 @@
        }
  
        let pinned = draggedTab.pinned;
@@ -361,7 +362,7 @@ index fa96568d366fd3608f9bd583fa793150bd815c8b..2ef63a6b462f28029f02decf14ad93de
        );
  
        if (this.#rtlMode) {
-@@ -2347,8 +2385,12 @@
+@@ -2347,8 +2384,12 @@
          (lastMovingTabScreen + tabSize);
        translate = Math.min(Math.max(translate, firstBound), lastBound);
  
@@ -376,7 +377,25 @@ index fa96568d366fd3608f9bd583fa793150bd815c8b..2ef63a6b462f28029f02decf14ad93de
        }
  
        dragData.translatePos = translate;
-@@ -2541,8 +2583,9 @@
+@@ -2484,12 +2525,16 @@
+       // Shift background tabs to leave a gap where the dragged tab
+       // would currently be dropped.
+       for (let tab of tabs) {
+-        if (tab == draggedTab) {
++        if (tab == draggedTab || (tab.group?.hasAttribute("split-view-group") && tab.group == draggedTab.group)) {
+           continue;
+         }
+         let shift = getTabShift(tab, newIndex);
+         let transform = shift ? `${translateAxis}(${shift}px)` : "";
++        if (tab.group?.hasAttribute("split-view-group")) {
++          tab.group.style.transform = transform;
++        } else {
+         tab.style.transform = transform;
++        }
+         if (tab.group?.tabs[0] == tab) {
+           tab.group.style.setProperty(
+             "--tabgroup-dragover-transform",
+@@ -2541,8 +2586,9 @@
        );
      }
  
@@ -388,7 +407,7 @@ index fa96568d366fd3608f9bd583fa793150bd815c8b..2ef63a6b462f28029f02decf14ad93de
          return;
        }
  
-@@ -2553,6 +2596,7 @@
+@@ -2553,6 +2599,7 @@
          tab.style.transform = "";
          if (tab.group) {
            tab.group.style.removeProperty("--tabgroup-dragover-transform");
@@ -396,7 +415,7 @@ index fa96568d366fd3608f9bd583fa793150bd815c8b..2ef63a6b462f28029f02decf14ad93de
          }
          tab.removeAttribute("dragover-createGroup");
        }
-@@ -2604,7 +2648,7 @@
+@@ -2604,7 +2651,7 @@
            movingTab._moveTogetherSelectedTabsData.newIndex = movingTabNewIndex;
            movingTab._moveTogetherSelectedTabsData.animate = false;
          };
@@ -405,7 +424,7 @@ index fa96568d366fd3608f9bd583fa793150bd815c8b..2ef63a6b462f28029f02decf14ad93de
            postTransitionCleanup();
          } else {
            let onTransitionEnd = transitionendEvent => {
-@@ -2707,9 +2751,9 @@
+@@ -2707,9 +2754,9 @@
        function newIndex(aTab, index) {
          // Don't allow mixing pinned and unpinned tabs.
          if (aTab.pinned) {
@@ -417,7 +436,7 @@ index fa96568d366fd3608f9bd583fa793150bd815c8b..2ef63a6b462f28029f02decf14ad93de
        }
      }
  
-@@ -2793,7 +2837,7 @@
+@@ -2793,7 +2840,7 @@
      }
  
      _notifyBackgroundTab(aTab) {