Misc comments to facilitate update for people who nilly-willy copied entire chunks of internal widgets to create their own.

imgui.cpp

@@ -4730,7 +4730,8 @@ bool ImGui::IsItemHovered(ImGuiHoveredFlags flags)
     return true;
 }
 
-// Internal facing ItemHoverable() used when submitting widgets. Differs slightly from IsItemHovered().
+// Internal facing ItemHoverable() used when submitting widgets. THIS IS A SUBMISSION NOT A HOVER CHECK.
+// Returns whether the item was hovered, logic differs slightly from IsItemHovered().
 // (this does not rely on LastItemData it can be called from a ButtonBehavior() call not following an ItemAdd() call)
 // FIXME-LEGACY: the 'ImGuiItemFlags item_flags' parameter was added on 2023-06-28.
 // If you used this in your legacy/custom widgets code:
@@ -4742,6 +4743,7 @@ bool ImGui::ItemHoverable(const ImRect& bb, ImGuiID id, ImGuiItemFlags item_flag
     ImGuiWindow* window = g.CurrentWindow;
 
     // Detect ID conflicts
+    // (this is specifically done here by comparing on hover because it allows us a detection of duplicates that is algorithmically extra cheap, 1 u32 compare per item. No O(log N) lookup whatsoever)
 #ifndef IMGUI_DISABLE_DEBUG_TOOLS
     if (id != 0 && g.HoveredIdPreviousFrame == id && (item_flags & ImGuiItemFlags_AllowDuplicateId) == 0)
     {

imgui_internal.h

@@ -976,6 +976,7 @@ enum ImGuiItemStatusFlags_
     ImGuiItemStatusFlags_Visible            = 1 << 8,   // [WIP] Set when item is overlapping the current clipping rectangle (Used internally. Please don't use yet: API/system will change as we refactor Itemadd()).
     ImGuiItemStatusFlags_HasClipRect        = 1 << 9,   // g.LastItemData.ClipRect is valid.
     ImGuiItemStatusFlags_HasShortcut        = 1 << 10,  // g.LastItemData.Shortcut valid. Set by SetNextItemShortcut() -> ItemAdd().
+    //ImGuiItemStatusFlags_FocusedByTabbing = 1 << 8,   // Removed IN 1.90.1 (Dec 2023). The trigger is part of g.NavActivateId. See commit 54c1bdeceb.
 
     // Additional status + semantic for ImGuiTestEngine
 #ifdef IMGUI_ENABLE_TEST_ENGINE
@@ -1028,6 +1029,7 @@ enum ImGuiButtonFlagsPrivate_
     ImGuiButtonFlags_NoFocus                = 1 << 22,  // [EXPERIMENTAL: Not very well specced]. Don't focus parent window when clicking.
     ImGuiButtonFlags_PressedOnMask_         = ImGuiButtonFlags_PressedOnClick | ImGuiButtonFlags_PressedOnClickRelease | ImGuiButtonFlags_PressedOnClickReleaseAnywhere | ImGuiButtonFlags_PressedOnRelease | ImGuiButtonFlags_PressedOnDoubleClick | ImGuiButtonFlags_PressedOnDragDropHold,
     ImGuiButtonFlags_PressedOnDefault_      = ImGuiButtonFlags_PressedOnClickRelease,
+    //ImGuiButtonFlags_NoKeyModifiers       = ImGuiButtonFlags_NoKeyModsAllowed, // Renamed in 1.91.4
 };
 
 // Extend ImGuiComboFlags_
@@ -1678,6 +1680,7 @@ enum ImGuiNavRenderCursorFlags_
     ImGuiNavHighlightFlags_Compact          = ImGuiNavRenderCursorFlags_Compact,    // Renamed in 1.91.4
     ImGuiNavHighlightFlags_AlwaysDraw       = ImGuiNavRenderCursorFlags_AlwaysDraw, // Renamed in 1.91.4
     ImGuiNavHighlightFlags_NoRounding       = ImGuiNavRenderCursorFlags_NoRounding, // Renamed in 1.91.4
+    //ImGuiNavHighlightFlags_TypeThin       = ImGuiNavRenderCursorFlags_Compact,    // Renamed in 1.90.2
 #endif
 };
 
@@ -2269,18 +2272,19 @@ struct ImGuiContext
     ImGuiWindow*            NavWindow;                          // Focused window for navigation. Could be called 'FocusedWindow'
     ImGuiID                 NavFocusScopeId;                    // Focused focus scope (e.g. selection code often wants to "clear other items" when landing on an item of the same scope)
     ImGuiNavLayer           NavLayer;                           // Focused layer (main scrolling layer, or menu/title bar layer)
-    ImGuiID                 NavActivateId;                      // ~~ (g.ActiveId == 0) && (IsKeyPressed(ImGuiKey_Space) || IsKeyDown(ImGuiKey_Enter) || IsKeyPressed(ImGuiKey_NavGamepadActivate)) ? NavId : 0, also set when calling ActivateItem()
+    ImGuiID                 NavActivateId;                      // ~~ (g.ActiveId == 0) && (IsKeyPressed(ImGuiKey_Space) || IsKeyDown(ImGuiKey_Enter) || IsKeyPressed(ImGuiKey_NavGamepadActivate)) ? NavId : 0, also set when calling ActivateItemByID()
     ImGuiID                 NavActivateDownId;                  // ~~ IsKeyDown(ImGuiKey_Space) || IsKeyDown(ImGuiKey_Enter) || IsKeyDown(ImGuiKey_NavGamepadActivate) ? NavId : 0
     ImGuiID                 NavActivatePressedId;               // ~~ IsKeyPressed(ImGuiKey_Space) || IsKeyPressed(ImGuiKey_Enter) || IsKeyPressed(ImGuiKey_NavGamepadActivate) ? NavId : 0 (no repeat)
     ImGuiActivateFlags      NavActivateFlags;
     ImVector<ImGuiFocusScopeData> NavFocusRoute;                // Reversed copy focus scope stack for NavId (should contains NavFocusScopeId). This essentially follow the window->ParentWindowForFocusRoute chain.
     ImGuiID                 NavHighlightActivatedId;
     float                   NavHighlightActivatedTimer;
-    ImGuiID                 NavNextActivateId;                  // Set by ActivateItem(), queued until next frame.
+    ImGuiID                 NavNextActivateId;                  // Set by ActivateItemByID(), queued until next frame.
     ImGuiActivateFlags      NavNextActivateFlags;
     ImGuiInputSource        NavInputSource;                     // Keyboard or Gamepad mode? THIS CAN ONLY BE ImGuiInputSource_Keyboard or ImGuiInputSource_Mouse
     ImGuiSelectionUserData  NavLastValidSelectionUserData;      // Last valid data passed to SetNextItemSelectionUser(), or -1. For current window. Not reset when focusing an item that doesn't have selection data.
     ImS8                    NavCursorHideFrames;
+    //ImGuiID               NavActivateInputId;                 // Removed in 1.89.4 (July 2023). This is now part of g.NavActivateId and sets g.NavActivateFlags |= ImGuiActivateFlags_PreferInput. See commit c9a53aa74, issue #5606.
 
     // Navigation: Init & Move Requests
     bool                    NavAnyRequest;                      // ~~ NavMoveRequest || NavInitRequest this is to perform early out in ItemAdd()
@@ -3281,7 +3285,7 @@ namespace ImGui
     // This should be part of a larger set of API: FocusItem(offset = -1), FocusItemByID(id), ActivateItem(offset = -1), ActivateItemByID(id) etc. which are
     // much harder to design and implement than expected. I have a couple of private branches on this matter but it's not simple. For now implementing the easy ones.
     IMGUI_API void          FocusItem();                    // Focus last item (no selection/activation).
-    IMGUI_API void          ActivateItemByID(ImGuiID id);   // Activate an item by ID (button, checkbox, tree node etc.). Activation is queued and processed on the next frame when the item is encountered again.
+    IMGUI_API void          ActivateItemByID(ImGuiID id);   // Activate an item by ID (button, checkbox, tree node etc.). Activation is queued and processed on the next frame when the item is encountered again. Was called 'ActivateItem()' before 1.89.7.
 
     // Inputs
     // FIXME: Eventually we should aim to move e.g. IsActiveIdUsingKey() into IsKeyXXX functions.
@@ -3663,6 +3667,7 @@ namespace ImGui
     //inline bool   TreeNodeBehaviorIsOpen(ImGuiID id, ImGuiTreeNodeFlags flags = 0)    { return TreeNodeUpdateNextOpen(id, flags); }   // Renamed in 1.89
     //inline bool   IsKeyPressedMap(ImGuiKey key, bool repeat = true)                   { IM_ASSERT(IsNamedKey(key)); return IsKeyPressed(key, repeat); } // Removed in 1.87: Mapping from named key is always identity!
 
+    // Refactored focus/nav/tabbing system in 1.82 and 1.84. If you have old/custom copy-and-pasted widgets which used FocusableItemRegister():
     // Refactored focus/nav/tabbing system in 1.82 and 1.84. If you have old/custom copy-and-pasted widgets which used FocusableItemRegister():
     //  (Old) IMGUI_VERSION_NUM  < 18209: using 'ItemAdd(....)'                              and 'bool tab_focused = FocusableItemRegister(...)'
     //  (Old) IMGUI_VERSION_NUM >= 18209: using 'ItemAdd(..., ImGuiItemAddFlags_Focusable)'  and 'bool tab_focused = (g.LastItemData.StatusFlags & ImGuiItemStatusFlags_Focused) != 0'

imgui_widgets.cpp

@@ -573,7 +573,8 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
     bool pressed = false;
     bool hovered = ItemHoverable(bb, id, item_flags);
 
-    // Special mode for Drag and Drop where holding button pressed for a long time while dragging another item triggers the button
+    // Special mode for Drag and Drop used by openables (tree nodes, tabs etc.)
+    // where holding the button pressed for a long time while drag a payload item triggers the button.
     if (g.DragDropActive && (flags & ImGuiButtonFlags_PressedOnDragDropHold) && !(g.DragDropSourceFlags & ImGuiDragDropFlags_SourceNoHoldToOpenOthers))
         if (IsItemHovered(ImGuiHoveredFlags_AllowWhenBlockedByActiveItem))
         {