1)The bottleneck of rendering was removed and rendering speed approximately doubled than the previous.
I found it that the some type of drawing lines in OpenGL was very slow.
The application used the VBO objects and called the following OpenGL command to draw lines. It was the bottleneck. I had to use glPolygonMode to draw polygon edges.
::glDrawArrays(GL_LINE_STRIP, i, size);
2) I put new tabs in the ribbon bar because there was no room for putting on new command buttons.
The Home Tab
The View Tab
The IFC Tab
The Option Tab