ImGui::Begin("test overlap");
        ImVec2 p = ImGui::GetCursorScreenPos();
        if (ImGui::Button("blah1", ImVec2(500,500)))
            printf("blah1\n");
        ImGui::SetItemAllowOverlap();
        ImGui::SetCursorScreenPos(ImVec2(p.x+100,p.y+100));
        if (ImGui::Button("blah2", ImVec2(100,100)))
            printf("blah2\n");
        ImGui::End();