1) Launch TC
2) Draw a 3D object
3) Render it several times by applying different rendering types (wireframe, draft, quality, advanced)
Issue: A time will come when the object disappears. When pressing Ctrl+A, it reappears but in a wireframe mode. Zooming in and out doesn't have any effect over it. Sometimes the screen turns out black along with leaving different traces inside the drawing.
Since option Background render is enabled, the rendering is interrupted when a key or mouse button is pressed.
In this case, the render is interrupted before the sphere (see screenshot-1)
When selected (pressing Ctrl+A), rendering is interrupted and the 3D object with selector box is drawn on top of the image in wireframe mode.