Version: v1.70 WIP
Branch: docking

Window is unable to undock with InputInt.
Able to undock when collapsing header is closed (IE InputInt is not called).
Example code:

if (ImGui::Begin("Testing"))
{
    if (ImGui::CollapsingHeader("Test"))
    {
        int someInt = 1;
        if(ImGui::InputInt("", &someInt))
        {
            someInt = max(1, someInt); // do something
        }
    }
}
ImGui::End();

Related if InputInt has a label ImGui::InputInt("What?", &someInt) it is able to undock.

EDIT: edited as it looks to be an issue with input int and not collapsing header.

EDIT 2: occurs with InputText and InputFloat too.