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.
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
// 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)