CreateControlCustom destroy issues

Folks,

We've just started using XT, and we're having some issues.

We create a Windows Slider control, and then dock it using the following:

void Foo::AddThumbWheel(CXTPRibbonGroup* pGroup, AppCommand* command, int width, bool startGroup)
{
     // Create the Slider control and add it to the bar.
     CSliderCtrl* wndSlider = new CSliderCtrl();
     wndSlider->Create(TBS_HORZ | TBS_NOTICKS | WS_CHILD | WS_VISIBLE, CRect(0, 0, width, 19), this, command->GetID());
     wndSlider->SetRangeMax(255);
     CXTPControlCustom* pControlSlider = CXTPControlCustom::CreateControlCustom(wndSlider);
     pControlSlider->SetBorders(0,1,0,0); // (right, top, left, bottom)
     pGroup->Add(pControlSlider, command->GetID());
}

The problem is, when pGroup is destroyed (via m_pRibbonBar->RemoveTab( tab ); ), the slider does not disappear, but stays on the ribbon bar.

Are we adding the control incorrectly?

Thanks much, folks. I've spent a day tearing my hair out over this.