- update to 1.90:
* BeginChild(): Upgraded 'bool border = false' parameter to
'ImGuiChildFlags flags = 0'.
* Added ImGuiChildFlags_Border value. As with our prior
"bool-to-flags" API updates, the ImGuiChildFlags_Border
value is guaranteed to be == true forever to ensure a
smoother transition, meaning all existing calls will still
work.
* BeginChildFrame()/EndChildFrame(): removed functions in
favor of using BeginChild() with the ImGuiChildFlags_FrameStyle
flag.
* IO: Removed io.MetricsActiveAllocations introduced in
1.63, was displayed in Metrics and unlikely to
be accessed by end-user. Value still visible in the UI and
easily to recompute from a delta.
* Commented out runtime support for hardcoded ~0 or
0x01..0x0F rounding flags values for
AddRect()/AddRectFilled()/PathRect()/AddImageRounded().

* too many changes to list here, see https://github.com/ocornut/imgui/releases/tag/v1.89.1
ship any actual functionality. ImGui suppose to be used as sources