Scrollbar: Fixed an issue where scrollbars wouldn't display on the frame following a frame where all child window contents would be culled.

Demo: Fixed a small bug with scrolling demo.
Metrics: Tweaks.

docs/CHANGELOG.txt

@@ -63,6 +63,8 @@ Other Changes:
   multi-line label and no frame padding, such as: multi-line text, small button, tree node item, etc.
   The second item was correctly offset to match text baseline, and would interact/display correctly,
   but it wouldn't push the contents area boundary low enough.
+- Scrollbar: Fixed an issue where scrollbars wouldn't display on the frame following a frame where
+  all child window contents would be culled.
 - ColorPicker: Fixed SV triangle gradient to block (broken in 1.73). (#2864, #2711). [@lewa-j]
 - TreeNode: Fixed combination of ImGuiTreeNodeFlags_SpanFullWidth and ImGuiTreeNodeFlags_OpenOnArrow
   incorrectly locating the arrow hit position to the left of the frame. (#2451, #2438, #1897)

imgui.cpp

@@ -5054,6 +5054,9 @@ void ImGui::RenderWindowDecorations(ImGuiWindow* window, const ImRect& title_bar
     ImGuiStyle& style = g.Style;
     ImGuiWindowFlags flags = window->Flags;
 
+    // Ensure that ScrollBar doesn't read last frame's SkipItems
+    window->SkipItems = false;
+
     // Draw window + handle manual resize
     // As we highlight the title bar when want_focus is set, multiple reappearing windows will have have their title bar highlighted on their reappearing frame.
     const float window_rounding = window->WindowRounding;
@@ -9754,7 +9757,10 @@ void ImGui::ShowMetricsWindow(bool* p_open)
                 ImGui::BulletText("%s: NULL", label);
                 return;
             }
-            if (!ImGui::TreeNode(window, "%s '%s', %d @ 0x%p", label, window->Name, (window->Active || window->WasActive), window))
+            bool open = ImGui::TreeNode(window, "%s '%s', %d @ 0x%p", label, window->Name, (window->Active || window->WasActive), window);
+            if (ImGui::IsItemHovered() && window->WasActive)
+                ImGui::GetForegroundDrawList()->AddRect(window->Pos, window->Pos + window->Size, IM_COL32(255, 255, 0, 255));
+            if (!open)
                 return;
             ImGuiWindowFlags flags = window->Flags;
             NodeDrawList(window, window->DrawList, "DrawList");
@@ -9763,7 +9769,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
                 (flags & ImGuiWindowFlags_ChildWindow)  ? "Child " : "",      (flags & ImGuiWindowFlags_Tooltip)     ? "Tooltip "   : "",  (flags & ImGuiWindowFlags_Popup) ? "Popup " : "",
                 (flags & ImGuiWindowFlags_Modal)        ? "Modal " : "",      (flags & ImGuiWindowFlags_ChildMenu)   ? "ChildMenu " : "",  (flags & ImGuiWindowFlags_NoSavedSettings) ? "NoSavedSettings " : "",
                 (flags & ImGuiWindowFlags_NoMouseInputs)? "NoMouseInputs":"", (flags & ImGuiWindowFlags_NoNavInputs) ? "NoNavInputs" : "", (flags & ImGuiWindowFlags_AlwaysAutoResize) ? "AlwaysAutoResize" : "");
-            ImGui::BulletText("Scroll: (%.2f/%.2f,%.2f/%.2f)", window->Scroll.x, window->ScrollMax.x, window->Scroll.y, window->ScrollMax.y);
+            ImGui::BulletText("Scroll: (%.2f/%.2f,%.2f/%.2f) Scrollbar:%s%s", window->Scroll.x, window->ScrollMax.x, window->Scroll.y, window->ScrollMax.y, window->ScrollbarX ? "X" : "", window->ScrollbarY ? "Y" : "");
             ImGui::BulletText("Active: %d/%d, WriteAccessed: %d, BeginOrderWithinContext: %d", window->Active, window->WasActive, window->WriteAccessed, (window->Active || window->WasActive) ? window->BeginOrderWithinContext : -1);
             ImGui::BulletText("Appearing: %d, Hidden: %d (CanSkip %d Cannot %d), SkipItems: %d", window->Appearing, window->Hidden, window->HiddenFramesCanSkipItems, window->HiddenFramesCannotSkipItems, window->SkipItems);
             ImGui::BulletText("NavLastIds: 0x%08X,0x%08X, NavLayerActiveMask: %X", window->NavLastIds[0], window->NavLastIds[1], window->DC.NavLayerActiveMask);
@@ -9821,7 +9827,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
     };
 
     Funcs::NodeWindows(g.Windows, "Windows");
-    if (ImGui::TreeNode("DrawList", "Active DrawLists (%d)", g.DrawDataBuilder.Layers[0].Size))
+    if (ImGui::TreeNode("DrawLists", "Active DrawLists (%d)", g.DrawDataBuilder.Layers[0].Size))
     {
         for (int i = 0; i < g.DrawDataBuilder.Layers[0].Size; i++)
             Funcs::NodeDrawList(NULL, g.DrawDataBuilder.Layers[0][i], "DrawList");

imgui_demo.cpp

@@ -2215,7 +2215,7 @@ static void ShowDemoWindowLayout()
             ImGui::TextUnformatted(names[i]);
 
             ImGuiWindowFlags child_flags = enable_extra_decorations ? ImGuiWindowFlags_MenuBar : 0;
-            ImGui::BeginChild(ImGui::GetID((void*)(intptr_t)i), ImVec2(child_w, 200.0f), true, child_flags);
+            bool window_visible = ImGui::BeginChild(ImGui::GetID((void*)(intptr_t)i), ImVec2(child_w, 200.0f), true, child_flags);
             if (ImGui::BeginMenuBar())
             {
                 ImGui::TextUnformatted("abc");
@@ -2225,16 +2225,19 @@ static void ShowDemoWindowLayout()
                 ImGui::SetScrollY(scroll_to_off_px);
             if (scroll_to_pos)
                 ImGui::SetScrollFromPosY(ImGui::GetCursorStartPos().y + scroll_to_pos_px, i * 0.25f);
-            for (int item = 0; item < 100; item++)
+            if (window_visible) // Avoid calling SetScrollHereY when running with culled items
             {
-                if (enable_track && item == track_item)
+                for (int item = 0; item < 100; item++)
                 {
-                    ImGui::TextColored(ImVec4(1,1,0,1), "Item %d", item);
-                    ImGui::SetScrollHereY(i * 0.25f); // 0.0f:top, 0.5f:center, 1.0f:bottom
-                }
-                else
-                {
-                    ImGui::Text("Item %d", item);
+                    if (enable_track && item == track_item)
+                    {
+                        ImGui::TextColored(ImVec4(1, 1, 0, 1), "Item %d", item);
+                        ImGui::SetScrollHereY(i * 0.25f); // 0.0f:top, 0.5f:center, 1.0f:bottom
+                    }
+                    else
+                    {
+                        ImGui::Text("Item %d", item);
+                    }
                 }
             }
             float scroll_y = ImGui::GetScrollY();
@@ -2253,23 +2256,26 @@ static void ShowDemoWindowLayout()
         {
             float child_height = ImGui::GetTextLineHeight() + style.ScrollbarSize + style.WindowPadding.y * 2.0f;
             ImGuiWindowFlags child_flags = ImGuiWindowFlags_HorizontalScrollbar | (enable_extra_decorations ? ImGuiWindowFlags_AlwaysVerticalScrollbar : 0);
-            ImGui::BeginChild(ImGui::GetID((void*)(intptr_t)i), ImVec2(-100, child_height), true, child_flags);
+            bool window_visible = ImGui::BeginChild(ImGui::GetID((void*)(intptr_t)i), ImVec2(-100, child_height), true, child_flags);
             if (scroll_to_off)
                 ImGui::SetScrollX(scroll_to_off_px);
             if (scroll_to_pos)
                 ImGui::SetScrollFromPosX(ImGui::GetCursorStartPos().x + scroll_to_pos_px, i * 0.25f);
-            for (int item = 0; item < 100; item++)
+            if (window_visible) // Avoid calling SetScrollHereY when running with culled items
             {
-                if (enable_track && item == track_item)
-                {
-                    ImGui::TextColored(ImVec4(1, 1, 0, 1), "Item %d", item);
-                    ImGui::SetScrollHereX(i * 0.25f); // 0.0f:left, 0.5f:center, 1.0f:right
-                }
-                else
+                for (int item = 0; item < 100; item++)
                 {
-                    ImGui::Text("Item %d", item);
+                    if (enable_track && item == track_item)
+                    {
+                        ImGui::TextColored(ImVec4(1, 1, 0, 1), "Item %d", item);
+                        ImGui::SetScrollHereX(i * 0.25f); // 0.0f:left, 0.5f:center, 1.0f:right
+                    }
+                    else
+                    {
+                        ImGui::Text("Item %d", item);
+                    }
+                    ImGui::SameLine();
                 }
-                ImGui::SameLine();
             }
             float scroll_x = ImGui::GetScrollX();
             float scroll_max_x = ImGui::GetScrollMaxX();