Alpha channel for block colors is not properly rendered in real time

[Dreikblack]

Before first render only first button had new color which looks correct

After applying same half-transparent color to both buttons in real time.

#include "UltraEngine.h"

using namespace UltraEngine;

shared_ptr<Window> window;
shared_ptr<Framebuffer> framebuffer;
shared_ptr<World> world;
shared_ptr<Interface> ui;
shared_ptr<Camera> uiCamera;

shared_ptr<Widget> btn;
shared_ptr<Widget> btn2;

static bool EventCallback(const Event& e, shared_ptr<Object> extra)
{
    Print("Callback");
    return true;
}

void initGui()
{
    auto default_font = LoadFont("Fonts\\arial.ttf");
    ui = CreateInterface(world, default_font, framebuffer->GetSize());
    ui->SetRenderLayers(2);
    ui->root->SetColor(1.0f, 0.0f, 0.0f, 1.0f);
    uiCamera = CreateCamera(world, PROJECTION_ORTHOGRAPHIC);
    uiCamera->SetPosition((float)framebuffer->GetSize().x * 0.5f, (float)framebuffer->GetSize().y * 0.5f, 0);
    uiCamera->SetRenderLayers(2);
    uiCamera->SetClearMode(CLEAR_DEPTH);
    btn = CreateButton("Btn", 20, 20, 100, 100, ui->root);
    btn2 = CreateButton("Btn", 20, 150, 100, 100, ui->root);
}

int main(int argc, const char* argv[])
{
    //Get the displays
    auto displays = GetDisplays();

    //Create a window
    window = CreateWindow("Ultra Engine", 0, 0, 300, 300, displays[0], WINDOW_CENTER | WINDOW_TITLEBAR);

    //Create a world
    world = CreateWorld();

    //Create a framebuffer
    framebuffer = CreateFramebuffer(window);

    //Create a camera    
    auto camera = CreateCamera(world);
    camera->SetClearColor(0, 0, 0);

    initGui();

    ListenEvent(EVENT_DATA, NULL, EventCallback, btn);
    auto color = Vec4(0.5, 0, 1, 0.5f);
    btn->SetColor(color);

    //Main loop
    while (window->Closed() == false and window->KeyDown(KEY_ESCAPE) == false)
    {
        if (window->KeyDown(KEY_SPACE))
        {
            btn->SetColor(color);
            btn2->SetColor(color);
        }
        world->Update();
        world->Render(framebuffer);
    }
    return 0;
}