DockBuilderCopyDockSpace crashes when windows not in remapping list are docked in a split

[cfillion]

Version/Branch of Dear ImGui:

Version: 1.89.1
Branch: docking

My Issue:

Using DockBuilderCopyDockSpace to move the contents of a dockspace to another crashes if the dockspace is split, contains a window in the first child (top or left) and nothing in the second child (bottom or right). (It works as expected in the opposite case: something in the second child and nothing in the first.)

Video

Standalone, minimal, complete and verifiable example:

#include <imgui/imgui_internal.h>

if(ImGui::Begin("Main")) {
  if(ImGui::Button("Crash Me")) {
    ImVector<const char *> remap;
    ImGui::DockBuilderCopyDockSpace(~0, ~1, &remap);
  }
  ImGui::DockSpace(~0, { 300.f, 300.f });
  ImGui::SameLine();
  ImGui::DockSpace(~1, { 300.f, 300.f });
}
ImGui::End();

if(ImGui::Begin("Dock Me"))
  ImGui::Text("Lorem ipsum");
ImGui::End();

[ocornut]

Thank you for reporting this.
This happened when the window in the split section is not in the remapping list.
Fixed with 6939676

[cfillion]

Thanks and happy new year! 🎉