Internals: using ItemAdd() consistently for internal items: windows & tables resize grips/borders, ScrollbarEx().

This put an extra flag check in ItemAdd() but essentially reduce inconsistency with windows decorations not using this. Useful for debugging.
It however buries the info/blurs the line about what it means to not use ItemAdd() since they are now doing it much less.

imgui.cpp

@@ -5874,7 +5874,7 @@ static bool ImGui::UpdateWindowManualResize(ImGuiWindow* window, const ImVec2& s
         if (resize_rect.Min.x > resize_rect.Max.x) ImSwap(resize_rect.Min.x, resize_rect.Max.x);
         if (resize_rect.Min.y > resize_rect.Max.y) ImSwap(resize_rect.Min.y, resize_rect.Max.y);
         ImGuiID resize_grip_id = window->GetID(resize_grip_n); // == GetWindowResizeCornerID()
-        KeepAliveID(resize_grip_id);
+        ItemAdd(resize_rect, resize_grip_id, NULL, ImGuiItemFlags_NoNav);
         ButtonBehavior(resize_rect, resize_grip_id, &hovered, &held, ImGuiButtonFlags_FlattenChildren | ImGuiButtonFlags_NoNavFocus);
         //GetForegroundDrawList(window)->AddRect(resize_rect.Min, resize_rect.Max, IM_COL32(255, 255, 0, 255));
         if (hovered || held)
@@ -5910,7 +5910,7 @@ static bool ImGui::UpdateWindowManualResize(ImGuiWindow* window, const ImVec2& s
         bool hovered, held;
         ImRect border_rect = GetResizeBorderRect(window, border_n, grip_hover_inner_size, WINDOWS_HOVER_PADDING);
         ImGuiID border_id = window->GetID(border_n + 4); // == GetWindowResizeBorderID()
-        KeepAliveID(border_id);
+        ItemAdd(border_rect, border_id, NULL, ImGuiItemFlags_NoNav);
         ButtonBehavior(border_rect, border_id, &hovered, &held, ImGuiButtonFlags_FlattenChildren | ImGuiButtonFlags_NoNavFocus);
         //GetForegroundDrawLists(window)->AddRect(border_rect.Min, border_rect.Max, IM_COL32(255, 255, 0, 255));
         if ((hovered && g.HoveredIdTimer > WINDOWS_RESIZE_FROM_EDGES_FEEDBACK_TIMER) || held)
@@ -8650,11 +8650,14 @@ bool ImGui::ItemAdd(const ImRect& bb, ImGuiID id, const ImRect* nav_bb_arg, ImGu
         //      to reach unclipped widgets. This would work if user had explicit scrolling control (e.g. mapped on a stick).
         // We intentionally don't check if g.NavWindow != NULL because g.NavAnyRequest should only be set when it is non null.
         // If we crash on a NULL g.NavWindow we need to fix the bug elsewhere.
-        window->DC.NavLayersActiveMaskNext |= (1 << window->DC.NavLayerCurrent);
-        if (g.NavId == id || g.NavAnyRequest)
-            if (g.NavWindow->RootWindowForNav == window->RootWindowForNav)
-                if (window == g.NavWindow || ((window->Flags | g.NavWindow->Flags) & ImGuiWindowFlags_NavFlattened))
-                    NavProcessItem();
+        if (!(g.LastItemData.InFlags & ImGuiItemFlags_NoNav))
+        {
+            window->DC.NavLayersActiveMaskNext |= (1 << window->DC.NavLayerCurrent);
+            if (g.NavId == id || g.NavAnyRequest)
+                if (g.NavWindow->RootWindowForNav == window->RootWindowForNav)
+                    if (window == g.NavWindow || ((window->Flags | g.NavWindow->Flags) & ImGuiWindowFlags_NavFlattened))
+                        NavProcessItem();
+        }
 
         // [DEBUG] People keep stumbling on this problem and using "" as identifier in the root of a window instead of "##something".
         // Empty identifier are valid and useful in a small amount of cases, but 99.9% of the time you want to use "##something".
@@ -10172,7 +10175,7 @@ static void ImGui::NavProcessItem()
             if (is_tab_stop || (g.NavMoveFlags & ImGuiNavMoveFlags_FocusApi))
                 NavProcessItemForTabbingRequest(id);
         }
-        else if ((g.NavId != id || (g.NavMoveFlags & ImGuiNavMoveFlags_AllowCurrentNavId)) && !(item_flags & (ImGuiItemFlags_Disabled | ImGuiItemFlags_NoNav)))
+        else if ((g.NavId != id || (g.NavMoveFlags & ImGuiNavMoveFlags_AllowCurrentNavId)) && !(item_flags & ImGuiItemFlags_Disabled))
         {
             ImGuiNavItemData* result = (window == g.NavWindow) ? &g.NavMoveResultLocal : &g.NavMoveResultOther;
             if (!is_tabbing)

imgui_internal.h

@@ -850,7 +850,7 @@ enum ImGuiButtonFlagsPrivate_
     ImGuiButtonFlags_AlignTextBaseLine      = 1 << 15,  // vertically align button to match text baseline - ButtonEx() only // FIXME: Should be removed and handled by SmallButton(), not possible currently because of DC.CursorPosPrevLine
     ImGuiButtonFlags_NoKeyModifiers         = 1 << 16,  // disable mouse interaction if a key modifier is held
     ImGuiButtonFlags_NoHoldingActiveId      = 1 << 17,  // don't set ActiveId while holding the mouse (ImGuiButtonFlags_PressedOnClick only)
-    ImGuiButtonFlags_NoNavFocus             = 1 << 18,  // don't override navigation focus when activated
+    ImGuiButtonFlags_NoNavFocus             = 1 << 18,  // don't override navigation focus when activated (FIXME: this is essentially used everytime an item uses ImGuiItemFlags_NoNav, but because legacy specs don't requires LastItemData to be set ButtonBehavior(), we can't poll g.LastItemData.InFlags)
     ImGuiButtonFlags_NoHoveredOnFocus       = 1 << 19,  // don't report as hovered when nav focus is on this item
     ImGuiButtonFlags_PressedOnMask_         = ImGuiButtonFlags_PressedOnClick | ImGuiButtonFlags_PressedOnClickRelease | ImGuiButtonFlags_PressedOnClickReleaseAnywhere | ImGuiButtonFlags_PressedOnRelease | ImGuiButtonFlags_PressedOnDoubleClick | ImGuiButtonFlags_PressedOnDragDropHold,
     ImGuiButtonFlags_PressedOnDefault_      = ImGuiButtonFlags_PressedOnClickRelease,

imgui_tables.cpp

@@ -1171,8 +1171,8 @@ void ImGui::TableUpdateBorders(ImGuiTable* table)
 
         ImGuiID column_id = TableGetColumnResizeID(table, column_n, table->InstanceCurrent);
         ImRect hit_rect(column->MaxX - hit_half_width, hit_y1, column->MaxX + hit_half_width, border_y2_hit);
+        ItemAdd(hit_rect, column_id, NULL, ImGuiItemFlags_NoNav);
         //GetForegroundDrawList()->AddRect(hit_rect.Min, hit_rect.Max, IM_COL32(255, 0, 0, 100));
-        KeepAliveID(column_id);
 
         bool hovered = false, held = false;
         bool pressed = ButtonBehavior(hit_rect, column_id, &hovered, &held, ImGuiButtonFlags_FlattenChildren | ImGuiButtonFlags_AllowItemOverlap | ImGuiButtonFlags_PressedOnClick | ImGuiButtonFlags_PressedOnDoubleClick | ImGuiButtonFlags_NoNavFocus);
@@ -4022,8 +4022,7 @@ void ImGui::EndColumns()
             const ImGuiID column_id = columns->ID + ImGuiID(n);
             const float column_hit_hw = COLUMNS_HIT_RECT_HALF_WIDTH;
             const ImRect column_hit_rect(ImVec2(x - column_hit_hw, y1), ImVec2(x + column_hit_hw, y2));
-            KeepAliveID(column_id);
-            if (IsClippedEx(column_hit_rect, column_id)) // FIXME: Can be removed or replaced with a lower-level test
+            if (!ItemAdd(column_hit_rect, column_id, NULL, ImGuiItemFlags_NoNav))
                 continue;
 
             bool hovered = false, held = false;

imgui_widgets.cpp

@@ -925,8 +925,6 @@ bool ImGui::ScrollbarEx(const ImRect& bb_frame, ImGuiID id, ImGuiAxis axis, ImS6
     if (window->SkipItems)
         return false;
 
-    KeepAliveID(id);
-
     const float bb_frame_width = bb_frame.GetWidth();
     const float bb_frame_height = bb_frame.GetHeight();
     if (bb_frame_width <= 0.0f || bb_frame_height <= 0.0f)
@@ -958,6 +956,7 @@ bool ImGui::ScrollbarEx(const ImRect& bb_frame, ImGuiID id, ImGuiAxis axis, ImS6
     // Handle input right away. None of the code of Begin() is relying on scrolling position before calling Scrollbar().
     bool held = false;
     bool hovered = false;
+    ItemAdd(bb_frame, id, NULL, ImGuiItemFlags_NoNav);
     ButtonBehavior(bb, id, &hovered, &held, ImGuiButtonFlags_NoNavFocus);
 
     const ImS64 scroll_max = ImMax((ImS64)1, size_contents_v - size_avail_v);
@@ -1477,11 +1476,7 @@ bool ImGui::SplitterBehavior(const ImRect& bb, ImGuiID id, ImGuiAxis axis, float
     ImGuiContext& g = *GImGui;
     ImGuiWindow* window = g.CurrentWindow;
 
-    const ImGuiItemFlags item_flags_backup = g.CurrentItemFlags;
-    g.CurrentItemFlags |= ImGuiItemFlags_NoNav | ImGuiItemFlags_NoNavDefaultFocus;
-    bool item_add = ItemAdd(bb, id);
-    g.CurrentItemFlags = item_flags_backup;
-    if (!item_add)
+    if (!ItemAdd(bb, id, NULL, ImGuiItemFlags_NoNav))
         return false;
 
     bool hovered, held;
@@ -6834,7 +6829,7 @@ void ImGui::EndMenuBar()
             // To do so we claim focus back, restore NavId and then process the movement request for yet another frame.
             // This involve a one-frame delay which isn't very problematic in this situation. We could remove it by scoring in advance for multiple window (probably not worth bothering)
             const ImGuiNavLayer layer = ImGuiNavLayer_Menu;
-            IM_ASSERT(window->DC.NavLayersActiveMaskNext & (1 << layer)); // Sanity check
+            IM_ASSERT(window->DC.NavLayersActiveMaskNext & (1 << layer)); // Sanity check (FIXME: Seems unnecessary)
             FocusWindow(window);
             SetNavID(window->NavLastIds[layer], layer, 0, window->NavRectRel[layer]);
             g.NavDisableHighlight = true; // Hide highlight for the current frame so we don't see the intermediary selection.
@@ -8059,7 +8054,7 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     IMGUI_TEST_ENGINE_ITEM_INFO(id, label, g.LastItemData.StatusFlags);
     if (p_open && !*p_open)
     {
-        ItemAdd(ImRect(), id, NULL, ImGuiItemFlags_NoNav | ImGuiItemFlags_NoNavDefaultFocus);
+        ItemAdd(ImRect(), id, NULL, ImGuiItemFlags_NoNav);
         return false;
     }
 
@@ -8131,7 +8126,7 @@ bool    ImGui::TabItemEx(ImGuiTabBar* tab_bar, const char* label, bool* p_open,
     // and then gets submitted again, the tabs will have 'tab_appearing=true' but 'tab_is_new=false'.
     if (tab_appearing && (!tab_bar_appearing || tab_is_new))
     {
-        ItemAdd(ImRect(), id, NULL, ImGuiItemFlags_NoNav | ImGuiItemFlags_NoNavDefaultFocus);
+        ItemAdd(ImRect(), id, NULL, ImGuiItemFlags_NoNav);
         if (is_tab_button)
             return false;
         return tab_contents_visible;