From c34f708ae4decbb8623b2d7deb57157dcad65eb2 Mon Sep 17 00:00:00 2001
From: rich2014 <rich2014.git@outlook.com>
Date: Thu, 12 Oct 2023 22:59:15 +0800
Subject: [PATCH] Cocoa/TabControl: exttabRemoveTabViewItem() refactored

---
 lcl/interfaces/cocoa/cocoatabcontrols.pas | 47 +++++------------------
 1 file changed, 9 insertions(+), 38 deletions(-)

diff --git a/lcl/interfaces/cocoa/cocoatabcontrols.pas b/lcl/interfaces/cocoa/cocoatabcontrols.pas
index d33f764a30..2ab1b15064 100644
--- a/lcl/interfaces/cocoa/cocoatabcontrols.pas
+++ b/lcl/interfaces/cocoa/cocoatabcontrols.pas
@@ -868,50 +868,21 @@ begin
     removedIndex := exttabIndexOfTabViewItem( removedTabPage );
     isRemovingCurrentPage:= (removedIndex=currentIndex);
 
-    if fulltabs.count=1 then begin
-      // there is only one Page, so must be removing current Page,
-      // the selectedItem must be lost
-      fulltabs.removeObjectAtIndex( removedIndex );
-      removeTabViewItem( removedTabPage );
-    end else if isRemovingCurrentPage then begin
-      // removing current Page, and there is at least one other Page.
-      // to keep the Page position stable and reduce selection changed events:
-      // 1. if the current page is on the rightmost of the visible TabView,
-      //    try add the Next Page to the visible TabView first
-      // 2. then look at the TabView again and if it still only has one page,
-      //    that means there is no Next Page, then there must be a prev Page,
-      //    insert it into the TabView
-      // 3. if there is the next Page, select it, thne removedPage will be auto
-      //    removed in UpdateTabAndArrowVisibility(), otherwise remove the
-      //    removedPage directly, and the prev Page will be auto selected.
-      // 4. finally remove the Page to be removed in fulltabs
-      if currentIndex < fulltabs.count-1 then
-        nextTabPage:= NSTabViewItem( fulltabs.objectAtIndex(currentIndex+1) )
-      else
-        nextTabPage:= nil;
-      if (currentIndex=visibleRightIndex) and Assigned(nextTabPage) then begin // 1
-        addTabViewItem( nextTabPage );
-        inc( visibleRightIndex );
-      end;
-      if numberOfTabViewItems=1 then begin                                     // 2
-        prevTabPage:= NSTabViewItem( fulltabs.objectAtIndex(currentIndex-1) );
-        insertTabViewItem_atIndex( prevTabPage, 0 );
-      end;
-      if Assigned(nextTabPage) then begin                                      // 3
-        selectTabViewItem( nextTabPage );
-      end else begin
-        removeTabViewItem( removedTabPage );
-      end;
-      fulltabs.removeObjectAtIndex( removedIndex );                            // 4
-      if removedIndex <= currentIndex then begin
+    fulltabs.removeObjectAtIndex( removedIndex );
+
+    if isRemovingCurrentPage then begin
+      // removing current page
+      attachAllTabs;
+      if currentIndex = fulltabs.count then begin
         dec( currentIndex );
-        dec( leftKeepAmount );
+        removeTabViewItem( removedTabPage );
+      end else begin
+        selectTabViewItemAtIndex( currentIndex );
       end;
     end else begin
       // not removing current page
       // only fulltabs need to be changed,
       // visible TabView auto updated in UpdateTabAndArrowVisibility()
-      fulltabs.removeObjectAtIndex( removedIndex );
       if removedIndex < currentIndex then begin
         dec( currentIndex );
         if (removedIndex=visibleLeftIndex) and (removedIndex=currentIndex) then