Moved ImGuiButtonFlags_AllowOverlap from imgui_internal.h to imgui.h + standardize comments.

docs/CHANGELOG.txt

@@ -115,6 +115,9 @@ Other Changes:
   - Implemented a custom tweak to extend hit-testing bounding box when window is sitting
     at the edge of a viewport (e.g. fullscreen or docked window), so that e.g. mouse the
     mouse at the extreme of the screen will reach the scrollbar. (#9276)
+- Button:
+  - Moved ImGuiButtonFlags_AllowOverlap from imgui_internal.h to imgui.h,
+    as a convenience for when using e.g. InvisibleButton().
 - Focus: fixed fallback "Debug" window temporarily taking focus and setting io.WantCaptureKeyboard
   for one frame on e.g. application boot if no other windows are submitted. (#9243)
 - Demo: fixed IMGUI_DEMO_MARKER locations for examples applets. (#9261, #3689) [@pthom]

imgui.h

@@ -1001,7 +1001,7 @@ namespace ImGui
     IMGUI_API void          SetNavCursorVisible(bool visible);                                  // alter visibility of keyboard/gamepad cursor. by default: show when using an arrow key, hide when clicking with mouse.
 
     // Overlapping mode
-    IMGUI_API void          SetNextItemAllowOverlap();                                          // allow next item to be overlapped by a subsequent item. Useful with invisible buttons, selectable, treenode covering an area where subsequent items may need to be added. Note that both Selectable() and TreeNode() have dedicated flags doing this.
+    IMGUI_API void          SetNextItemAllowOverlap();                                          // allow next item to be overlapped by a subsequent item. Typically useful with InvisibleButton(), Selectable(), TreeNode() covering an area where subsequent items may need to be added. Note that both Selectable() and TreeNode() have dedicated flags doing this.
 
     // Item/Widgets Utilities and Query Functions
     // - Most of the functions are referring to the previous Item that has been submitted.
@@ -1303,7 +1303,7 @@ enum ImGuiTreeNodeFlags_
     ImGuiTreeNodeFlags_None                 = 0,
     ImGuiTreeNodeFlags_Selected             = 1 << 0,   // Draw as selected
     ImGuiTreeNodeFlags_Framed               = 1 << 1,   // Draw frame with background (e.g. for CollapsingHeader)
-    ImGuiTreeNodeFlags_AllowOverlap         = 1 << 2,   // Hit testing to allow subsequent widgets to overlap this one
+    ImGuiTreeNodeFlags_AllowOverlap         = 1 << 2,   // Hit testing will allow subsequent widgets to overlap this one. Require previous frame HoveredId to match before being usable. Shortcut to calling SetNextItemAllowOverlap().
     ImGuiTreeNodeFlags_NoTreePushOnOpen     = 1 << 3,   // Don't do a TreePush() when open (e.g. for CollapsingHeader) = no extra indent nor pushing on ID stack
     ImGuiTreeNodeFlags_NoAutoOpenOnLog      = 1 << 4,   // Don't automatically and temporarily open node when Logging is active (by default logging will automatically open tree nodes)
     ImGuiTreeNodeFlags_DefaultOpen          = 1 << 5,   // Default node to be open
@@ -1363,7 +1363,7 @@ enum ImGuiSelectableFlags_
     ImGuiSelectableFlags_SpanAllColumns     = 1 << 1,   // Frame will span all columns of its container table (text will still fit in current column)
     ImGuiSelectableFlags_AllowDoubleClick   = 1 << 2,   // Generate press events on double clicks too
     ImGuiSelectableFlags_Disabled           = 1 << 3,   // Cannot be selected, display grayed out text
-    ImGuiSelectableFlags_AllowOverlap       = 1 << 4,   // (WIP) Hit testing to allow subsequent widgets to overlap this one
+    ImGuiSelectableFlags_AllowOverlap       = 1 << 4,   // Hit testing will allow subsequent widgets to overlap this one. Require previous frame HoveredId to match before being usable. Shortcut to calling SetNextItemAllowOverlap().
     ImGuiSelectableFlags_Highlight          = 1 << 5,   // Make the item be displayed as if it is hovered
     ImGuiSelectableFlags_SelectOnNav        = 1 << 6,   // Auto-select when moved into, unless Ctrl is held. Automatic when in a BeginMultiSelect() block.
 
@@ -1870,6 +1870,7 @@ enum ImGuiButtonFlags_
     ImGuiButtonFlags_MouseButtonMiddle      = 1 << 2,   // React on center mouse button
     ImGuiButtonFlags_MouseButtonMask_       = ImGuiButtonFlags_MouseButtonLeft | ImGuiButtonFlags_MouseButtonRight | ImGuiButtonFlags_MouseButtonMiddle, // [Internal]
     ImGuiButtonFlags_EnableNav              = 1 << 3,   // InvisibleButton(): do not disable navigation/tabbing. Otherwise disabled by default.
+    ImGuiButtonFlags_AllowOverlap           = 1 << 12,  // Hit testing will allow subsequent widgets to overlap this one. Require previous frame HoveredId to match before being usable. Shortcut to calling SetNextItemAllowOverlap().
 };
 
 // Flags for ColorEdit3() / ColorEdit4() / ColorPicker3() / ColorPicker4() / ColorButton()

imgui_internal.h

@@ -1038,7 +1038,6 @@ enum ImGuiButtonFlagsPrivate_
     ImGuiButtonFlags_PressedOnDragDropHold  = 1 << 9,   // return true when held into while we are drag and dropping another item (used by e.g. tree nodes, collapsing headers)
     //ImGuiButtonFlags_Repeat               = 1 << 10,  // hold to repeat -> use ImGuiItemFlags_ButtonRepeat instead.
     ImGuiButtonFlags_FlattenChildren        = 1 << 11,  // allow interactions even if a child window is overlapping
-    ImGuiButtonFlags_AllowOverlap           = 1 << 12,  // require previous frame HoveredId to either match id or be null before being usable.
     //ImGuiButtonFlags_DontClosePopups      = 1 << 13,  // disable automatically closing parent popup on press
     //ImGuiButtonFlags_Disabled             = 1 << 14,  // disable interactions -> use BeginDisabled() or ImGuiItemFlags_Disabled
     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