Drag and Drop: moved "drag souce doesn't report as hovered" from ButtonBehavior() to ItemHoverable().

Ensure DragXXX, SliderXXXX, InputText, PlotXXX follow same logic. Amend 251f178a6, a33f0d1f7

docs/CHANGELOG.txt

@@ -75,6 +75,9 @@ Other changes:
 - Clipper: Rework inner logic to allow functioning with a zero-clear constructor.
   This is order to facilitate usage for language bindings (e.g cimgui or dear_binding)
   where user may not be callinga constructor manually. (#5856)
+- Drag and Drop: Apply default behavior of drag source not reporting itself as hovered
+  at lower-level, so DragXXX, SliderXXX, InputXXX, Plot widgets are fullfilling it.
+  (Behavior doesn't apply when ImGuiDragDropFlags_SourceNoDisableHover is set).
 - Modals: In the case of nested modal, made sure that focused or appearing windows are
   moved below the lowest blocking modal (rather than the highest one). (#4317)
 - GetKeyName(): Fixed assert with ImGuiMod_XXX values when IMGUI_DISABLE_OBSOLETE_KEYIO is set.

imgui.cpp

@@ -4050,6 +4050,10 @@ bool ImGui::ItemHoverable(const ImRect& bb, ImGuiID id)
         return false;
     }
 
+    // Drag source doesn't report as hovered
+    if (g.DragDropActive && g.DragDropPayload.SourceId == id && !(g.DragDropSourceFlags & ImGuiDragDropFlags_SourceNoDisableHover))
+        return false;
+
     // We exceptionally allow this function to be called with id==0 to allow using it for easy high-level
     // hover test in widgets code. We could also decide to split this function is two.
     if (id != 0)

imgui_widgets.cpp

@@ -506,10 +506,6 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
     bool pressed = false;
     bool hovered = ItemHoverable(bb, id);
 
-    // Drag source doesn't report as hovered
-    if (hovered && g.DragDropActive && g.DragDropPayload.SourceId == id && !(g.DragDropSourceFlags & ImGuiDragDropFlags_SourceNoDisableHover))
-        hovered = false;
-
     // Special mode for Drag and Drop where holding button pressed for a long time while dragging another item triggers the button
     if (g.DragDropActive && (flags & ImGuiButtonFlags_PressedOnDragDropHold) && !(g.DragDropSourceFlags & ImGuiDragDropFlags_SourceNoHoldToOpenOthers))
         if (IsItemHovered(ImGuiHoveredFlags_AllowWhenBlockedByActiveItem))