No MIDI controller function when Ti Control Centre open

This seems a bit weird.

If I have a project open in Cubase Studio 4 using just VST synths I can assign the Virus' to control the VST parameters. For example i'll asign the filter cutoff knob to the filter cutoff in Sylenth.

As soon as I open up the Virus control centre in the same project I can no longer do this. The MIDI learn function on whatever VST synth i'm using either doesn't work or the Virus doesn't want to play ball.

Is this a common problem or just a setting in the VCC?

Cheers

My error sorry.

I simply meant the Virus Ti in a project as a VST.

Once I do this I cannot use the midi learn from any of the software synths.