The background color of ImGui windows seems not correct when it is set to transparent white

[zhangliang07]

It seems like a problem for a long time, and still exists in recent versions.
The color of the ImGui's windows' background in DiligentCore apps is incorrect, when the background color is set to transparent white, such as this code:
ImGui::GetStyle().Colors[ImGuiCol_WindowBg] = ImVec4(1.0f, 1.0f, 1.0f, 0.5f);

The background color shows a transparent dark gray, but it should be transparent white.
With the same setting, the color is correct in the independent ImGui app without DiligentEngine.
In 2.5.3 the color shows right. This is the environment I used with when the problem occurs:
DiligentCore: v2.5.4~v2.5.6
Integrated ImGui: 1.89.1, 1.91.3
OS: Windows 11 with d3d11, d3d12, opengl, and valkan

I hope it can be fixed because I really need a light translucent style :)

The background color in DiligentEngine:

Hoped background color of ImGui app without DiligentEngine: