Updated ImGui.

3rdparty/dear-imgui/imgui.cpp

@@ -807,7 +807,7 @@ static const float WINDOWS_MOUSE_WHEEL_SCROLL_LOCK_TIMER    = 2.00f;    // Lock
 static void             SetCurrentWindow(ImGuiWindow* window);
 static void             FindHoveredWindow();
 static ImGuiWindow*     CreateNewWindow(const char* name, ImGuiWindowFlags flags);
-static ImVec2           CalcNextScrollFromScrollTargetAndClamp(ImGuiWindow* window, bool snap_on_edges);
+static ImVec2           CalcNextScrollFromScrollTargetAndClamp(ImGuiWindow* window);
 
 static void             AddDrawListToDrawData(ImVector<ImDrawList*>* out_list, ImDrawList* draw_list);
 static void             AddWindowToSortBuffer(ImVector<ImGuiWindow*>* out_sorted_windows, ImGuiWindow* window);
@@ -3375,8 +3375,8 @@ void ImGui::UpdateMouseMovingWindowEndFrame()
                 if (!root_window->TitleBarRect().Contains(g.IO.MouseClickedPos[0]))
                     g.MovingWindow = NULL;
 
-            // Cancel moving if clicked over an item which was disabled or inhibited by popups
+            // Cancel moving if clicked over an item which was disabled or inhibited by popups (note that we know HoveredId == 0 already)
-            if (g.HoveredId == 0 && g.HoveredIdDisabled)
+            if (g.HoveredIdDisabled)
                 g.MovingWindow = NULL;
         }
         else if (root_window == NULL && g.NavWindow != NULL && GetTopMostPopupModal() == NULL)
@@ -5821,7 +5821,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->ScrollMax.y = ImMax(0.0f, window->ContentSize.y + window->WindowPadding.y * 2.0f - window->InnerRect.GetHeight());
 
         // Apply scrolling
-        window->Scroll = CalcNextScrollFromScrollTargetAndClamp(window, true);
+        window->Scroll = CalcNextScrollFromScrollTargetAndClamp(window);
         window->ScrollTarget = ImVec2(FLT_MAX, FLT_MAX);
 
         // DRAWING
@@ -5900,6 +5900,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->WorkRect.Min.y = ImFloor(window->InnerRect.Min.y - window->Scroll.y + ImMax(window->WindowPadding.y, window->WindowBorderSize));
         window->WorkRect.Max.x = window->WorkRect.Min.x + work_rect_size_x;
         window->WorkRect.Max.y = window->WorkRect.Min.y + work_rect_size_y;
+        window->ParentWorkRect = window->WorkRect;
 
         // [LEGACY] Content Region
         // FIXME-OBSOLETE: window->ContentRegionRect.Max is currently very misleading / partly faulty, but some BeginChild() patterns relies on it.
@@ -7327,30 +7328,20 @@ void ImGui::EndGroup()
 // [SECTION] SCROLLING
 //-----------------------------------------------------------------------------
 
-static ImVec2 CalcNextScrollFromScrollTargetAndClamp(ImGuiWindow* window, bool snap_on_edges)
+static ImVec2 CalcNextScrollFromScrollTargetAndClamp(ImGuiWindow* window)
 {
-    ImGuiContext& g = *GImGui;
     ImVec2 scroll = window->Scroll;
     if (window->ScrollTarget.x < FLT_MAX)
     {
         float cr_x = window->ScrollTargetCenterRatio.x;
         float target_x = window->ScrollTarget.x;
-        if (snap_on_edges && cr_x <= 0.0f && target_x <= window->WindowPadding.x)
-            target_x = 0.0f;
-        else if (snap_on_edges && cr_x >= 1.0f && target_x >= window->ContentSize.x + window->WindowPadding.x + g.Style.ItemSpacing.x)
-            target_x = window->ContentSize.x + window->WindowPadding.x * 2.0f;
         scroll.x = target_x - cr_x * (window->SizeFull.x - window->ScrollbarSizes.x);
     }
     if (window->ScrollTarget.y < FLT_MAX)
     {
-        // 'snap_on_edges' allows for a discontinuity at the edge of scrolling limits to take account of WindowPadding so that scrolling to make the last item visible scroll far enough to see the padding.
         float decoration_up_height = window->TitleBarHeight() + window->MenuBarHeight();
         float cr_y = window->ScrollTargetCenterRatio.y;
         float target_y = window->ScrollTarget.y;
-        if (snap_on_edges && cr_y <= 0.0f && target_y <= window->WindowPadding.y)
-            target_y = 0.0f;
-        if (snap_on_edges && cr_y >= 1.0f && target_y >= window->ContentSize.y + window->WindowPadding.y + g.Style.ItemSpacing.y)
-            target_y = window->ContentSize.y + window->WindowPadding.y * 2.0f;
         scroll.y = target_y - cr_y * (window->SizeFull.y - window->ScrollbarSizes.y - decoration_up_height);
     }
     scroll.x = IM_FLOOR(ImMax(scroll.x, 0.0f));
@@ -7382,7 +7373,7 @@ ImVec2 ImGui::ScrollToBringRectIntoView(ImGuiWindow* window, const ImRect& item_
         else if (item_rect.Max.y >= window_rect.Max.y)
             SetScrollFromPosY(window, item_rect.Max.y - window->Pos.y + g.Style.ItemSpacing.y, 1.0f);
 
-        ImVec2 next_scroll = CalcNextScrollFromScrollTargetAndClamp(window, false);
+        ImVec2 next_scroll = CalcNextScrollFromScrollTargetAndClamp(window);
         delta_scroll = next_scroll - window->Scroll;
     }
 
@@ -7443,10 +7434,10 @@ void ImGui::SetScrollY(ImGuiWindow* window, float new_scroll_y)
     window->ScrollTargetCenterRatio.y = 0.0f;
 }
 
-
+// Note that a local position will vary depending on initial scroll value
+// We store a target position so centering can occur on the next frame when we are guaranteed to have a known window size
 void ImGui::SetScrollFromPosX(ImGuiWindow* window, float local_x, float center_x_ratio)
 {
-    // We store a target position so centering can occur on the next frame when we are guaranteed to have a known window size
     IM_ASSERT(center_x_ratio >= 0.0f && center_x_ratio <= 1.0f);
     window->ScrollTarget.x = IM_FLOOR(local_x + window->Scroll.x);
     window->ScrollTargetCenterRatio.x = center_x_ratio;
@@ -7454,10 +7445,8 @@ void ImGui::SetScrollFromPosX(ImGuiWindow* window, float local_x, float center_x
 
 void ImGui::SetScrollFromPosY(ImGuiWindow* window, float local_y, float center_y_ratio)
 {
-    // We store a target position so centering can occur on the next frame when we are guaranteed to have a known window size
     IM_ASSERT(center_y_ratio >= 0.0f && center_y_ratio <= 1.0f);
-    const float decoration_up_height = window->TitleBarHeight() + window->MenuBarHeight();
+    local_y -= window->TitleBarHeight() + window->MenuBarHeight(); // FIXME: Would be nice to have a more standardized access to our scrollable/client rect
-    local_y -= decoration_up_height;
     window->ScrollTarget.y = IM_FLOOR(local_y + window->Scroll.y);
     window->ScrollTargetCenterRatio.y = center_y_ratio;
 }
@@ -7474,15 +7463,34 @@ void ImGui::SetScrollFromPosY(float local_y, float center_y_ratio)
     SetScrollFromPosY(g.CurrentWindow, local_y, center_y_ratio);
 }
 
+// Tweak: snap on edges when aiming at an item very close to the edge,
+// So the difference between WindowPadding and ItemSpacing will be in the visible area after scrolling.
+// When we refactor the scrolling API this may be configurable with a flag?
+// Note that the effect for this won't be visible on X axis with default Style settings as WindowPadding.x == ItemSpacing.x by default.
+static float CalcScrollSnap(float target, float snap_min, float snap_max, float snap_threshold, float center_ratio)
+{
+    if (target <= snap_min + snap_threshold)
+        return ImLerp(snap_min, target, center_ratio);
+    if (target >= snap_max - snap_threshold)
+        return ImLerp(target, snap_max, center_ratio);
+    return target;
+}
+
 // center_x_ratio: 0.0f left of last item, 0.5f horizontal center of last item, 1.0f right of last item.
 void ImGui::SetScrollHereX(float center_x_ratio)
 {
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
-    float target_x = window->DC.LastItemRect.Min.x - window->Pos.x; // Left of last item, in window space
+    float spacing_x = g.Style.ItemSpacing.x;
-    float last_item_width = window->DC.LastItemRect.GetWidth();
+    float target_x = ImLerp(window->DC.LastItemRect.Min.x - spacing_x, window->DC.LastItemRect.Max.x + spacing_x, center_x_ratio);
-    target_x += (last_item_width * center_x_ratio) + (g.Style.ItemSpacing.x * (center_x_ratio - 0.5f) * 2.0f); // Precisely aim before, in the middle or after the last item.
+
-    SetScrollFromPosX(target_x, center_x_ratio);
+    // Tweak: snap on edges when aiming at an item very close to the edge
+    const float snap_x_threshold = ImMax(0.0f, window->WindowPadding.x - spacing_x);
+    const float snap_x_min = window->DC.CursorStartPos.x - window->WindowPadding.x;
+    const float snap_x_max = window->DC.CursorStartPos.x + window->ContentSize.x + window->WindowPadding.x;
+    target_x = CalcScrollSnap(target_x, snap_x_min, snap_x_max, snap_x_threshold, center_x_ratio);
+
+    SetScrollFromPosX(window, target_x - window->Pos.x, center_x_ratio);
 }
 
 // center_y_ratio: 0.0f top of last item, 0.5f vertical center of last item, 1.0f bottom of last item.
@@ -7490,9 +7498,16 @@ void ImGui::SetScrollHereY(float center_y_ratio)
 {
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
-    float target_y = window->DC.CursorPosPrevLine.y - window->Pos.y; // Top of last item, in window space
+    float spacing_y = g.Style.ItemSpacing.y;
-    target_y += (window->DC.PrevLineSize.y * center_y_ratio) + (g.Style.ItemSpacing.y * (center_y_ratio - 0.5f) * 2.0f); // Precisely aim above, in the middle or below the last line.
+    float target_y = ImLerp(window->DC.CursorPosPrevLine.y - spacing_y, window->DC.CursorPosPrevLine.y + window->DC.PrevLineSize.y + spacing_y, center_y_ratio);
-    SetScrollFromPosY(target_y, center_y_ratio);
+
+    // Tweak: snap on edges when aiming at an item very close to the edge
+    const float snap_y_threshold = ImMax(0.0f, window->WindowPadding.y - spacing_y);
+    const float snap_y_min = window->DC.CursorStartPos.y - window->WindowPadding.y;
+    const float snap_y_max = window->DC.CursorStartPos.y + window->ContentSize.y + window->WindowPadding.y;
+    target_y = CalcScrollSnap(target_y, snap_y_min, snap_y_max, snap_y_threshold, center_y_ratio);
+
+    SetScrollFromPosY(window, target_y - window->Pos.y, center_y_ratio);
 }
 
 //-----------------------------------------------------------------------------

3rdparty/dear-imgui/imgui.h

@@ -333,8 +333,8 @@ namespace ImGui
     // Windows Scrolling
     IMGUI_API float         GetScrollX();                                                   // get scrolling amount [0..GetScrollMaxX()]
     IMGUI_API float         GetScrollY();                                                   // get scrolling amount [0..GetScrollMaxY()]
-    IMGUI_API float         GetScrollMaxX();                                                // get maximum scrolling amount ~~ ContentSize.X - WindowSize.X
+    IMGUI_API float         GetScrollMaxX();                                                // get maximum scrolling amount ~~ ContentSize.x - WindowSize.x
-    IMGUI_API float         GetScrollMaxY();                                                // get maximum scrolling amount ~~ ContentSize.Y - WindowSize.Y
+    IMGUI_API float         GetScrollMaxY();                                                // get maximum scrolling amount ~~ ContentSize.y - WindowSize.y
     IMGUI_API void          SetScrollX(float scroll_x);                                     // set scrolling amount [0..GetScrollMaxX()]
     IMGUI_API void          SetScrollY(float scroll_y);                                     // set scrolling amount [0..GetScrollMaxY()]
     IMGUI_API void          SetScrollHereX(float center_x_ratio = 0.5f);                    // adjust scrolling amount to make current cursor position visible. center_x_ratio=0.0: left, 0.5: center, 1.0: right. When using to make a "default/current item" visible, consider using SetItemDefaultFocus() instead.

3rdparty/dear-imgui/imgui_demo.cpp

@@ -1960,7 +1960,7 @@ static void ShowDemoWindowWidgets()
 
 static void ShowDemoWindowLayout()
 {
-    if (!ImGui::CollapsingHeader("Layout"))
+    if (!ImGui::CollapsingHeader("Layout & Scrolling"))
         return;
 
     if (ImGui::TreeNode("Child windows"))
@@ -2490,11 +2490,9 @@ static void ShowDemoWindowLayout()
         ImGui::Spacing();
         HelpMarker(
             "Use SetScrollHereX() or SetScrollFromPosX() to scroll to a given horizontal position.\n\n"
-            "Using the \"Scroll To Pos\" button above will make the discontinuity at edges visible: "
+            "Because the clipping rectangle of most window hides half worth of WindowPadding on the "
-            "scrolling to the top/bottom/left/right-most item will add an additional WindowPadding to reflect "
+            "left/right, using SetScrollFromPosX(+1) will usually result in clipped text whereas the "
-            "on reaching the edge of the list.\n\nBecause the clipping rectangle of most window hides half "
+            "equivalent SetScrollFromPosY(+1) wouldn't.");
-            "worth of WindowPadding on the left/right, using SetScrollFromPosX(+1) will usually result in "
-            "clipped text whereas the equivalent SetScrollFromPosY(+1) wouldn't.");
         ImGui::PushID("##HorizontalScrolling");
         for (int i = 0; i < 5; i++)
         {
@@ -2684,23 +2682,66 @@ static void ShowDemoWindowLayout()
 
     if (ImGui::TreeNode("Clipping"))
     {
-        static ImVec2 size(100, 100), offset(50, 20);
+        static ImVec2 size(100.0f, 100.0f);
-        ImGui::TextWrapped(
+        static ImVec2 offset(30.0f, 30.0f);
-            "On a per-widget basis we are occasionally clipping text CPU-side if it won't fit in its frame. "
-            "Otherwise we are doing coarser clipping + passing a scissor rectangle to the renderer. "
-            "The system is designed to try minimizing both execution and CPU/GPU rendering cost.");
         ImGui::DragFloat2("size", (float*)&size, 0.5f, 1.0f, 200.0f, "%.0f");
-        ImGui::TextWrapped("(Click and drag)");
+        ImGui::TextWrapped("(Click and drag to scroll)");
-        ImVec2 pos = ImGui::GetCursorScreenPos();
+
-        ImVec4 clip_rect(pos.x, pos.y, pos.x + size.x, pos.y + size.y);
+        for (int n = 0; n < 3; n++)
+        {
+            if (n > 0)
+                ImGui::SameLine();
+            ImGui::PushID(n);
+            ImGui::BeginGroup(); // Lock X position
+
             ImGui::InvisibleButton("##empty", size);
-        if (ImGui::IsItemActive() && ImGui::IsMouseDragging(0))
+            if (ImGui::IsItemActive() && ImGui::IsMouseDragging(ImGuiMouseButton_Left))
             {
                 offset.x += ImGui::GetIO().MouseDelta.x;
                 offset.y += ImGui::GetIO().MouseDelta.y;
             }
-        ImGui::GetWindowDrawList()->AddRectFilled(pos, ImVec2(pos.x + size.x, pos.y + size.y), IM_COL32(90, 90, 120, 255));
+            const ImVec2 p0 = ImGui::GetItemRectMin();
-        ImGui::GetWindowDrawList()->AddText(ImGui::GetFont(), ImGui::GetFontSize()*2.0f, ImVec2(pos.x + offset.x, pos.y + offset.y), IM_COL32_WHITE, "Line 1 hello\nLine 2 clip me!", NULL, 0.0f, &clip_rect);
+            const ImVec2 p1 = ImGui::GetItemRectMax();
+            const char* text_str = "Line 1 hello\nLine 2 clip me!";
+            const ImVec2 text_pos = ImVec2(p0.x + offset.x, p0.y + offset.y);
+            ImDrawList* draw_list = ImGui::GetWindowDrawList();
+
+            switch (n)
+            {
+            case 0:
+                HelpMarker(
+                    "Using ImGui::PushClipRect():\n"
+                    "Will alter ImGui hit-testing logic + ImDrawList rendering.\n"
+                    "(use this if you want your clipping rectangle to affect interactions)");
+                ImGui::PushClipRect(p0, p1, true);
+                draw_list->AddRectFilled(p0, p1, IM_COL32(90, 90, 120, 255));
+                draw_list->AddText(text_pos, IM_COL32_WHITE, text_str);
+                ImGui::PopClipRect();
+                break;
+            case 1:
+                HelpMarker(
+                    "Using ImDrawList::PushClipRect():\n"
+                    "Will alter ImDrawList rendering only.\n"
+                    "(use this as a shortcut if you are only using ImDrawList calls)");
+                draw_list->PushClipRect(p0, p1, true);
+                draw_list->AddRectFilled(p0, p1, IM_COL32(90, 90, 120, 255));
+                draw_list->AddText(text_pos, IM_COL32_WHITE, text_str);
+                draw_list->PopClipRect();
+                break;
+            case 2:
+                HelpMarker(
+                    "Using ImDrawList::AddText() with a fine ClipRect:\n"
+                    "Will alter only this specific ImDrawList::AddText() rendering.\n"
+                    "(this is often used internally to avoid altering the clipping rectangle and minimize draw calls)");
+                ImVec4 clip_rect(p0.x, p0.y, p1.x, p1.y); // AddText() takes a ImVec4* here so let's convert.
+                draw_list->AddRectFilled(p0, p1, IM_COL32(90, 90, 120, 255));
+                draw_list->AddText(ImGui::GetFont(), ImGui::GetFontSize(), text_pos, IM_COL32_WHITE, text_str, NULL, 0.0f, &clip_rect);
+                break;
+            }
+            ImGui::EndGroup();
+            ImGui::PopID();
+        }
+
         ImGui::TreePop();
     }
 }
@@ -4952,8 +4993,7 @@ static void ShowExampleAppCustomRendering(bool* p_open)
 
         if (ImGui::BeginTabItem("Canvas"))
         {
-            struct ItemLine { ImVec2 p0, p1; ItemLine(const ImVec2& _p0, const ImVec2& _p1) { p0 = _p0; p1 = _p1; } };
+            static ImVector<ImVec2> points;
-            static ImVector<ItemLine> lines;
             static ImVec2 scrolling(0.0f, 0.0f);
             static bool opt_enable_grid = true;
             static bool opt_enable_context_menu = true;
@@ -4997,12 +5037,13 @@ static void ShowExampleAppCustomRendering(bool* p_open)
             // Add first and second point
             if (is_hovered && !adding_line && ImGui::IsMouseClicked(ImGuiMouseButton_Left))
             {
-                lines.push_back(ItemLine(mouse_pos_in_canvas, mouse_pos_in_canvas));
+                points.push_back(mouse_pos_in_canvas);
+                points.push_back(mouse_pos_in_canvas);
                 adding_line = true;
             }
             if (adding_line)
             {
-                lines.back().p1 = mouse_pos_in_canvas;
+                points.back() = mouse_pos_in_canvas;
                 if (!ImGui::IsMouseDown(ImGuiMouseButton_Left))
                     adding_line = false;
             }
@@ -5023,10 +5064,10 @@ static void ShowExampleAppCustomRendering(bool* p_open)
             if (ImGui::BeginPopup("context"))
             {
                 if (adding_line)
-                    lines.pop_back();
+                    points.resize(points.size() - 2);
                 adding_line = false;
-                if (ImGui::MenuItem("Remove one", NULL, false, lines.Size > 0)) { lines.pop_back(); }
+                if (ImGui::MenuItem("Remove one", NULL, false, points.Size > 0)) { points.resize(points.size() - 2); }
-                if (ImGui::MenuItem("Remove all", NULL, false, lines.Size > 0)) { lines.clear(); }
+                if (ImGui::MenuItem("Remove all", NULL, false, points.Size > 0)) { points.clear(); }
                 ImGui::EndPopup();
             }
 
@@ -5040,8 +5081,8 @@ static void ShowExampleAppCustomRendering(bool* p_open)
                 for (float y = fmodf(scrolling.y, GRID_STEP); y < canvas_sz.y; y += GRID_STEP)
                     draw_list->AddLine(ImVec2(canvas_p0.x, canvas_p0.y + y), ImVec2(canvas_p1.x, canvas_p0.y + y), IM_COL32(200, 200, 200, 40));
             }
-            for (int n = 0; n < lines.Size; n++)
+            for (int n = 0; n < points.Size; n += 2)
-                draw_list->AddLine(ImVec2(origin.x + lines[n].p0.x, origin.y + lines[n].p0.y), ImVec2(origin.x + lines[n].p1.x, origin.y + lines[n].p1.y), IM_COL32(255, 255, 0, 255), 2.0f);
+                draw_list->AddLine(ImVec2(origin.x + points[n].x, origin.y + points[n].y), ImVec2(origin.x + points[n + 1].x, origin.y + points[n + 1].y), IM_COL32(255, 255, 0, 255), 2.0f);
             draw_list->PopClipRect();
 
             ImGui::EndTabItem();

3rdparty/dear-imgui/imgui_internal.h

@@ -1015,7 +1015,7 @@ struct ImGuiColumns
     float               HostCursorMaxPosX;      // Backup of CursorMaxPos at the time of BeginColumns()
     ImRect              HostInitialClipRect;    // Backup of ClipRect at the time of BeginColumns()
     ImRect              HostBackupClipRect;     // Backup of ClipRect during PushColumnsBackground()/PopColumnsBackground()
-    ImRect              HostWorkRect;           // Backup of WorkRect at the time of BeginColumns()
+    ImRect              HostBackupParentWorkRect;//Backup of WorkRect at the time of BeginColumns()
     ImVector<ImGuiColumnData> Columns;
     ImDrawListSplitter  Splitter;
 
@@ -1612,7 +1612,8 @@ struct IMGUI_API ImGuiWindow
     ImRect                  OuterRectClipped;                   // == Window->Rect() just after setup in Begin(). == window->Rect() for root window.
     ImRect                  InnerRect;                          // Inner rectangle (omit title bar, menu bar, scroll bar)
     ImRect                  InnerClipRect;                      // == InnerRect shrunk by WindowPadding*0.5f on each side, clipped within viewport or parent clip rect.
-    ImRect                  WorkRect;                           // Cover the whole scrolling region, shrunk by WindowPadding*1.0f on each side. This is meant to replace ContentRegionRect over time (from 1.71+ onward).
+    ImRect                  WorkRect;                           // Initially covers the whole scrolling region. Reduced by containers e.g columns/tables when active. Shrunk by WindowPadding*1.0f on each side. This is meant to replace ContentRegionRect over time (from 1.71+ onward).
+    ImRect                  ParentWorkRect;                     // Backup of WorkRect before entering a container such as columns/tables. Used by e.g. SpanAllColumns functions to easily access. Stacked containers are responsible for maintaining this. // FIXME-WORKRECT: Could be a stack?
     ImRect                  ClipRect;                           // Current clipping/scissoring rectangle, evolve as we are using PushClipRect(), etc. == DrawList->clip_rect_stack.back().
     ImRect                  ContentRegionRect;                  // FIXME: This is currently confusing/misleading. It is essentially WorkRect but not handling of scrolling. We currently rely on it as right/bottom aligned sizing operation need some size to rely on.
     ImVec2ih                HitTestHoleSize;                    // Define an optional rectangular hole where mouse will pass-through the window.

3rdparty/dear-imgui/imgui_widgets.cpp

@@ -5719,8 +5719,8 @@ bool ImGui::Selectable(const char* label, bool selected, ImGuiSelectableFlags fl
     ItemSize(size, 0.0f);
 
     // Fill horizontal space
-    const float min_x = (flags & ImGuiSelectableFlags_SpanAllColumns) ? window->ContentRegionRect.Min.x : pos.x;
+    const float min_x = (flags & ImGuiSelectableFlags_SpanAllColumns) ? window->ParentWorkRect.Min.x : pos.x;
-    const float max_x = (flags & ImGuiSelectableFlags_SpanAllColumns) ? window->ContentRegionRect.Max.x : GetContentRegionMaxAbs().x;
+    const float max_x = (flags & ImGuiSelectableFlags_SpanAllColumns) ? window->ParentWorkRect.Max.x : window->WorkRect.Max.x;
     if (size_arg.x == 0.0f || (flags & ImGuiSelectableFlags_SpanAvailWidth))
         size.x = ImMax(label_size.x, max_x - min_x);
 
@@ -6672,9 +6672,9 @@ bool    ImGui::BeginTabBarEx(ImGuiTabBar* tab_bar, const ImRect& tab_bar_bb, ImG
     tab_bar->CurrFrameVisible = g.FrameCount;
     tab_bar->FramePadding = g.Style.FramePadding;
 
-    // Layout
+    // Set cursor pos in a way which only be used in the off-chance the user erroneously submits item before BeginTabItem(): items will overlap
-    ItemSize(ImVec2(tab_bar->OffsetMaxIdeal, tab_bar->BarRect.GetHeight()), tab_bar->FramePadding.y);
     window->DC.CursorPos.x = tab_bar->BarRect.Min.x;
+    window->DC.CursorPos.y = tab_bar->BarRect.Max.y + g.Style.ItemSpacing.y;
 
     // Draw separator
     const ImU32 col = GetColorU32((flags & ImGuiTabBarFlags_IsFocused) ? ImGuiCol_TabActive : ImGuiCol_TabUnfocusedActive);
@@ -6700,7 +6700,7 @@ void    ImGui::EndTabBar()
         IM_ASSERT_USER_ERROR(tab_bar != NULL, "Mismatched BeginTabBar()/EndTabBar()!");
         return;
     }
-    if (tab_bar->WantLayout)
+    if (tab_bar->WantLayout) // Fallback in case no TabItem have been submitted
         TabBarLayout(tab_bar);
 
     // Restore the last visible height if no tab is visible, this reduce vertical flicker/movement when a tabs gets removed without calling SetTabItemClosed().
@@ -6886,6 +6886,11 @@ static void ImGui::TabBarLayout(ImGuiTabBar* tab_bar)
     // Clear name buffers
     if ((tab_bar->Flags & ImGuiTabBarFlags_DockNode) == 0)
         tab_bar->TabsNames.Buf.resize(0);
+
+    // Actual layout in host window (we don't do it in BeginTabBar() so as not to waste an extra frame)
+    ImGuiWindow* window = g.CurrentWindow;
+    window->DC.CursorPos = tab_bar->BarRect.Min;
+    ItemSize(ImVec2(tab_bar->OffsetMaxIdeal, tab_bar->BarRect.GetHeight()), tab_bar->FramePadding.y);
 }
 
 // Dockables uses Name/ID in the global namespace. Non-dockable items use the ID stack.
@@ -7680,7 +7685,8 @@ void ImGui::BeginColumns(const char* str_id, int columns_count, ImGuiColumnsFlag
     columns->HostCursorPosY = window->DC.CursorPos.y;
     columns->HostCursorMaxPosX = window->DC.CursorMaxPos.x;
     columns->HostInitialClipRect = window->ClipRect;
-    columns->HostWorkRect = window->WorkRect;
+    columns->HostBackupParentWorkRect = window->ParentWorkRect;
+    window->ParentWorkRect = window->WorkRect;
 
     // Set state for first column
     // We aim so that the right-most column will have the same clipping width as other after being clipped by parent ClipRect
@@ -7860,7 +7866,8 @@ void ImGui::EndColumns()
     }
     columns->IsBeingResized = is_being_resized;
 
-    window->WorkRect = columns->HostWorkRect;
+    window->WorkRect = window->ParentWorkRect;
+    window->ParentWorkRect = columns->HostBackupParentWorkRect;
     window->DC.CurrentColumns = NULL;
     window->DC.ColumnsOffset.x = 0.0f;
     window->DC.CursorPos.x = IM_FLOOR(window->Pos.x + window->DC.Indent.x + window->DC.ColumnsOffset.x);