Weird behaviour when setting ImGuiStyle::Alpha before ImGui::Begin when docked about imgui HOT 2 CLOSED

However, in the scenario that there is a docked window A and a floating window B, when B is closed and a fade out occurs, the alpha of window A also changes. This only occurs while window A is docked. When undocked, it behaves as expected:

You are overriding global Alpha and not restoring it. So it leaks into those other windows and is used by the docking system inside NewFrame().
Use PushStyleVar(ImGuiStyleVar_Alpha, alpha); .... PopStyleVar() instead.

This seems to work:

{
    ImGui::PushStyleColor(ImGuiCol_WindowBg, ImVec4(0, 0, 0, 0));
    ImGui::DockSpaceOverViewport(ImGui::GetMainViewport(), ImGuiDockNodeFlags_PassthruCentralNode);
    ImGui::PopStyleColor();

    static float alpha = 0.7f;
    ImGui::SliderFloat("alpha", &alpha, 0.0f, 1.0f);
    ImGui::PushStyleVar(ImGuiStyleVar_Alpha, alpha);
    ImGui::PushStyleColor(ImGuiCol_WindowBg, ImVec4(1, 0, 0, 1));
    ImGui::Begin("Some window");
    ImGui::Text("Hello");
    ImGui::End();
    ImGui::PopStyleColor();
    ImGui::PopStyleVar();
}

Note that the TabItem itself doesn't use the specified alpha, it seems undesirable. The TabBar is owned by the dock node not a single window.

from imgui.

I see, this is much better, thank you.
Your note about the TabItem is reasonable and clears up part of my question, thanks.

Closing as no further questions.

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