diff --git a/imgui.cpp b/imgui.cpp
index 1333bc29..cde3c4ab 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -11125,7 +11125,7 @@ namespace ImGui
     static bool             DockNodeIsDropAllowed(ImGuiWindow* host_window, ImGuiWindow* payload_window);
     static void             DockNodePreviewDockCalc(ImGuiWindow* host_window, ImGuiDockNode* host_node, ImGuiWindow* payload_window, ImGuiDockPreviewData* preview_data, bool is_explicit_target, bool is_outer_docking);
     static void             DockNodePreviewDockRender(ImGuiWindow* host_window, ImGuiDockNode* host_node, ImGuiWindow* payload_window, const ImGuiDockPreviewData* preview_data);
-    static ImRect           DockNodeCalcTabBarRect(const ImGuiDockNode* node);
+    static void             DockNodeCalcTabBarLayout(const ImGuiDockNode* node, ImRect* out_title_rect, ImRect* out_tab_bar_rect, ImVec2* out_collapse_button_pos);
     static void             DockNodeCalcSplitRects(ImVec2& pos_old, ImVec2& size_old, ImVec2& pos_new, ImVec2& size_new, ImGuiDir dir, ImVec2 size_new_desired);
     static bool             DockNodeCalcDropRectsAndTestMousePos(const ImRect& parent, ImGuiDir dir, ImRect& out_draw, bool outer_docking, ImVec2* test_mouse_pos);
     static const char*      DockNodeGetHostWindowTitle(ImGuiDockNode* node, char* buf, int buf_size) { ImFormatString(buf, buf_size, "##DockNode_%02X", node->ID); return buf; }
@@ -12322,8 +12322,12 @@ static int IMGUI_CDECL TabItemComparerByDockOrder(const void* lhs, const void* r
 static ImGuiID ImGui::DockNodeUpdateTabListMenu(ImGuiDockNode* node, ImGuiTabBar* tab_bar)
 {
     // Try to position the menu so it is more likely to stays within the same viewport
+    ImGuiContext& g = *GImGui;
     ImGuiID ret_tab_id = 0;
-    SetNextWindowPos(ImVec2(node->Pos.x, node->Pos.y + GetFrameHeight()));
+    if (g.Style.WindowMenuButtonPosition == ImGuiDir_Left)
+        SetNextWindowPos(ImVec2(node->Pos.x, node->Pos.y + GetFrameHeight()), ImGuiCond_Always, ImVec2(0.0f, 0.0f));
+    else
+        SetNextWindowPos(ImVec2(node->Pos.x + node->Size.x, node->Pos.y + GetFrameHeight()), ImGuiCond_Always, ImVec2(1.0f, 0.0f));
     if (BeginPopup("#TabListMenu"))
     {
         node->IsFocused = true;
@@ -12419,15 +12423,19 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
         is_focused |= node->IsFocused;
     }
 
+    // Layout
+    ImRect title_bar_rect, tab_bar_rect;
+    ImVec2 collapse_button_pos;
+    DockNodeCalcTabBarLayout(node, &title_bar_rect, &tab_bar_rect, &collapse_button_pos);
+
     // Title bar
     if (is_focused)
         node->LastFrameFocused = g.FrameCount;
-    ImRect title_bar_rect = ImRect(node->Pos, node->Pos + ImVec2(node->Size.x, g.FontSize + style.FramePadding.y * 2.0f));
     ImU32 title_bar_col = GetColorU32(host_window->Collapsed ? ImGuiCol_TitleBgCollapsed : is_focused ? ImGuiCol_TitleBgActive : ImGuiCol_TitleBg);
     host_window->DrawList->AddRectFilled(title_bar_rect.Min, title_bar_rect.Max, title_bar_col, host_window->WindowRounding, ImDrawCornerFlags_Top);
 
     // Collapse button
-    if (CollapseButton(host_window->GetID("#COLLAPSE"), title_bar_rect.Min, node))
+    if (CollapseButton(host_window->GetID("#COLLAPSE"), collapse_button_pos, node))
         OpenPopup("#TabListMenu");
     if (IsItemActive())
         focus_tab_id = tab_bar->SelectedTabId;
@@ -12461,7 +12469,6 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
         tab_bar->SelectedTabId = tab_bar->NextSelectedTabId = tab_bar->Tabs.back().Window->ID;
 
     // Begin tab bar
-    const ImRect tab_bar_rect = DockNodeCalcTabBarRect(node);
     ImGuiTabBarFlags tab_bar_flags = ImGuiTabBarFlags_Reorderable | ImGuiTabBarFlags_AutoSelectNewTabs; // | ImGuiTabBarFlags_NoTabListScrollingButtons);
     tab_bar_flags |= ImGuiTabBarFlags_SaveSettings | ImGuiTabBarFlags_DockNode;
     if (!host_window->Collapsed && is_focused)
@@ -12621,15 +12628,27 @@ static bool ImGui::DockNodeIsDropAllowed(ImGuiWindow* host_window, ImGuiWindow*
     return false;
 }
 
-static ImRect ImGui::DockNodeCalcTabBarRect(const ImGuiDockNode* node)
+// FIXME: This is similar to RenderWindowTitleBarContents, may want to share code.
+static void ImGui::DockNodeCalcTabBarLayout(const ImGuiDockNode* node, ImRect* out_title_rect, ImRect* out_tab_bar_rect, ImVec2* out_collapse_button_pos)
 {
     ImGuiContext& g = *GImGui;
-    ImRect r = ImRect(node->Pos.x, node->Pos.y, node->Pos.x + node->Size.x, node->Pos.y + (g.FontSize + g.Style.FramePadding.y * 2.0f));
-    if (node->HasCollapseButton)
-        r.Min.x += g.Style.FramePadding.x + g.FontSize; // + g.Style.ItemInnerSpacing.x; // <-- Adding ItemInnerSpacing makes the title text moves slightly when in a tab bar. Instead we adjusted RenderArrowDockMenu()
-    // In DockNodeUpdateTabBar() we currently display a disabled close button even if there is none.
-    r.Max.x -= g.Style.FramePadding.x + g.FontSize + 1.0f;
-    return r;
+    ImRect r = ImRect(node->Pos.x, node->Pos.y, node->Pos.x + node->Size.x, node->Pos.y + g.FontSize + g.Style.FramePadding.y * 2.0f);
+    if (out_title_rect) { *out_title_rect = r; }
+
+    ImVec2 collapse_button_pos = r.Min;
+    r.Max.x -= g.Style.FramePadding.x + g.FontSize;// +1.0f; // In DockNodeUpdateTabBar() we currently display a disabled close button even if there is none.
+    if (node->HasCollapseButton && g.Style.WindowMenuButtonPosition == ImGuiDir_Left)
+    {
+        r.Min.x += g.Style.FramePadding.x + g.FontSize; // + g.Style.ItemInnerSpacing.x; // <-- Adding ItemInnerSpacing makes the title text moves slightly when in a docking tab bar. Instead we adjusted RenderArrowDockMenu()
+    }
+    else if (node->HasCollapseButton && g.Style.WindowMenuButtonPosition == ImGuiDir_Right)
+    {
+        r.Min.x += g.Style.FramePadding.x;
+        r.Max.x -= g.FontSize + g.Style.FramePadding.x;
+        collapse_button_pos = ImVec2(r.Max.x, r.Min.y);
+    }
+    if (out_tab_bar_rect) { *out_tab_bar_rect = r; }
+    if (out_collapse_button_pos) { *out_collapse_button_pos = collapse_button_pos; }
 }
 
 void ImGui::DockNodeCalcSplitRects(ImVec2& pos_old, ImVec2& size_old, ImVec2& pos_new, ImVec2& size_new, ImGuiDir dir, ImVec2 size_new_desired)
@@ -12832,7 +12851,8 @@ static void ImGui::DockNodePreviewDockRender(ImGuiWindow* host_window, ImGuiDock
     if (data->IsDropAllowed && can_preview_tabs && data->SplitDir == ImGuiDir_None && data->IsCenterAvailable)
     {
         // Compute target tab bar geometry so we can locate our preview tabs
-        ImRect tab_bar_rect = DockNodeCalcTabBarRect(&data->FutureNode);
+        ImRect tab_bar_rect;
+        DockNodeCalcTabBarLayout(&data->FutureNode, NULL, &tab_bar_rect, NULL);
         ImVec2 tab_pos = tab_bar_rect.Min;
         if (host_node && host_node->TabBar)
         {
diff --git a/imgui_widgets.cpp b/imgui_widgets.cpp
index 5e2acb13..22af6491 100644
--- a/imgui_widgets.cpp
+++ b/imgui_widgets.cpp
@@ -793,7 +793,7 @@ bool ImGui::CollapseButton(ImGuiID id, const ImVec2& pos, ImGuiDockNode* dock_no
         }
         else
         {
-            ImVec2 backup_active_click_offset = g.ActiveIdClickOffset;
+            ImVec2 backup_active_click_offset = g.ActiveIdClickOffset + (pos - window->Pos);
             StartMouseMovingWindow(window);
             g.ActiveIdClickOffset = backup_active_click_offset;
         }