The pipeline of he color is the following:

1) Convert the color to a RGBA-32-bit color space supported by
   OCIO. Unially, this color space coincides with the one use by
   the image.

2) OCIO applies Exposure and Gamma correction

3) If color management mode is not internal, OCIO converts
   the color space for the output device, otherwise the color
   is converted by the display converter explicitly.

4) Display converted converts the resulting data either in qt-widget
   color space or to the opengl-surface space.

The problem of Internal mode happened because steps 2 and 3 were
swapped, when in Internal mode. Now everything is applied in a correct
order.