Overlap: moved ImGuiItemflags_AllowOverlap handling from ButtoBehavior() to ItemHoverable() now that it is possible. (#6512, #3909, #517)

This allows DragXXX, SliderXXX, PlotXXX etc to honor SetNextItemAllowOverlap().

docs/CHANGELOG.txt

@@ -50,6 +50,10 @@ Breaking changes:
   - Renamed 'ImGuiSelectableFlags_AllowItemOverlap' to 'ImGuiSelectableFlags_AllowOverlap'
   - IsItemHovered: Changed behavior to return false when querying an item using AllowOverlap mode
     which is being overlapped. Added ImGuiHoveredFlags_AllowWhenOverlappedByItem. (#6512, #3909, #517)
+  - Selectable, TreeNode: When using ImGuiSelectableFlags_AllowOverlap/ImGuiTreeNodeFlags_AllowOverlap
+    and holding item held, overlapping widgets won't appear as hovered. (#6512, #3909)
+  - Most item types should now work with SetNextItemAllowOverlap(). (#6512, #3909, #517)
+  - Fixed first frame of an overlap highlighting underlying item if previous frame didn't hover anything.
   - Kept redirecting enums (will obsolete).
 
 Other changes:
@@ -77,10 +81,6 @@ Other changes:
   - IsItemHovered: Added _AllowWhenOverlappedByWindow to ignore window-overlap only.
     Option ImGuiHoveredFlags_AllowWhenOverlapped now expand into a combination of both
     _AllowWhenOverlappedByWindow + _AllowWhenOverlappedByItem, matching old behavior.
-- Overlapping items: (#6512, #3909, #517)
-  - Selectable, TreeNode: When using ImGuiSelectableFlags_AllowOverlap/ImGuiTreeNodeFlags_AllowOverlap
-    and holding item held, overlapping widgets won't appear as hovered. (#6512, #3909)
-  - Fixed first frame of an overlap highlighting underlying item if previous frame didn't hover anything.
 - IsWindowHovered: Added support for ImGuiHoveredFlags_Stationary.
 - IsWindowHovered, IsItemHovered: Assert when passed any unsupported flags.
 - Tables: Fixed a regression in 1.89.6 leading to the first column of tables with either

imgui.cpp

@@ -4069,6 +4069,15 @@ bool ImGui::ItemHoverable(const ImRect& bb, ImGuiID id, ImGuiItemFlags item_flag
             return false;
 
         SetHoveredID(id);
+
+        // AllowOverlap mode (rarely used) requires previous frame HoveredId to be null or to match.
+        // This allows using patterns where a later submitted widget overlaps a previous one. Generally perceived as a front-to-back hit-test.
+        if (item_flags & ImGuiItemflags_AllowOverlap)
+        {
+            g.HoveredIdAllowOverlap = true;
+            if (g.HoveredIdPreviousFrame != id)
+                return false;
+        }
     }
 
     // When disabled we'll return false but still set HoveredId

imgui_widgets.cpp

@@ -531,15 +531,6 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
     if (flatten_hovered_children)
         g.HoveredWindow = backup_hovered_window;
 
-    // AllowOverlap mode (rarely used) requires previous frame HoveredId to be null or to match. This allows using patterns where a later submitted widget overlaps a previous one.
-    if (item_flags & ImGuiItemflags_AllowOverlap)
-    {
-        if (hovered && g.HoveredIdPreviousFrame != id)
-            hovered = false;
-        if (g.HoveredId == id) // FIXME: Added this to match legacy SetItemAllowOverlap(). Investigate precise side-effects of using (hovered==true) instead?
-            g.HoveredIdAllowOverlap = true;
-    }
-
     // Mouse handling
     const ImGuiID test_owner_id = (flags & ImGuiButtonFlags_NoTestKeyOwner) ? ImGuiKeyOwner_Any : id;
     if (hovered)