fix: prevent pinned tabs from commingling with non-pinned tabs in split view

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 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d9296a455275 100644
+index 5f406ea5d09273c9b70b84eee24c6267f88692f8..adc4599c4d1722f8a6a0a636bba074a2b4b44527 100644
 --- a/browser/components/tabbrowser/content/tabbrowser.js
 +++ b/browser/components/tabbrowser/content/tabbrowser.js
 @@ -424,11 +424,50 @@
@@ -595,7 +595,18 @@ index 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d929
            neighbor.after(aTab);
          } else {
            this.tabContainer.insertBefore(aTab, neighbor);
-@@ -5908,6 +6061,9 @@
+@@ -5901,6 +6054,10 @@
+        * Bug 1955388 - prevent pinned tabs from commingling with non-pinned tabs
+        * when there are hidden tabs present
+        */
++      if (targetElement?.group?.hasAttribute("split-view-group")) {
++        targetElement = targetElement.group;
++      }
++
+       if (tab.pinned && !targetElement?.pinned) {
+         // prevent pinned tab from being dragged past a non-pinned tab
+         targetElement = this.tabs[this.pinnedTabCount - 1];
+@@ -5908,6 +6065,9 @@
        }
  
        let getContainer = () => {
@@ -605,7 +616,7 @@ index 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d929
          if (tab.pinned && this.tabContainer.verticalMode) {
            return this.tabContainer.verticalPinnedTabsContainer;
          }
-@@ -5937,7 +6093,7 @@
+@@ -5937,7 +6097,7 @@
      }
  
      moveTabToGroup(aTab, aGroup) {
@@ -614,7 +625,7 @@ index 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d929
          return;
        }
        if (aTab.group && aTab.group.id === aGroup.id) {
-@@ -5961,6 +6117,10 @@
+@@ -5961,6 +6121,10 @@
  
        moveActionCallback();
  
@@ -625,7 +636,7 @@ index 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d929
        // Clear tabs cache after moving nodes because the order of tabs may have
        // changed.
        this.tabContainer._invalidateCachedTabs();
-@@ -6015,7 +6175,7 @@
+@@ -6015,7 +6179,7 @@
          createLazyBrowser,
        };
  
@@ -634,7 +645,7 @@ index 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d929
        if (aIndex < numPinned || (aTab.pinned && aIndex == numPinned)) {
          params.pinned = true;
        }
-@@ -6765,7 +6925,7 @@
+@@ -6765,7 +6929,7 @@
              // preventDefault(). It will still raise the window if appropriate.
              break;
            }
@@ -643,7 +654,7 @@ index 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d929
            window.focus();
            aEvent.preventDefault();
            break;
-@@ -7671,6 +7831,7 @@
+@@ -7671,6 +7835,7 @@
              aWebProgress.isTopLevel
            ) {
              this.mTab.setAttribute("busy", "true");
@@ -651,7 +662,7 @@ index 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d929
              gBrowser._tabAttrModified(this.mTab, ["busy"]);
              this.mTab._notselectedsinceload = !this.mTab.selected;
            }
-@@ -8640,7 +8801,7 @@ var TabContextMenu = {
+@@ -8640,7 +8805,7 @@ var TabContextMenu = {
      );
      contextUnpinSelectedTabs.hidden =
        !this.contextTab.pinned || !this.multiselected;
@@ -660,7 +671,7 @@ index 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d929
      // Move Tab items
      let contextMoveTabOptions = document.getElementById(
        "context_moveTabOptions"
-@@ -8674,7 +8835,7 @@ var TabContextMenu = {
+@@ -8674,7 +8839,7 @@ var TabContextMenu = {
      let isFirstTab =
        !this.contextTabs[0].group &&
        (this.contextTabs[0] == visibleTabs[0] ||
@@ -669,7 +680,7 @@ index 5f406ea5d09273c9b70b84eee24c6267f88692f8..8e3dc2669c57ff59f66bcc0b0c45d929
      contextMoveTabToStart.disabled = isFirstTab && allSelectedTabsAdjacent;
  
      document.getElementById("context_openTabInWindow").disabled =
-@@ -8904,6 +9065,7 @@ var TabContextMenu = {
+@@ -8904,6 +9069,7 @@ var TabContextMenu = {
      if (this.contextTab.multiselected) {
        gBrowser.removeMultiSelectedTabs();
      } else {