To reproduce:
- Add a RadToggleButtonElement to the quick access toolbar.

Workaround:
RadToggleButton button = new RadToggleButton();
button.Text = "Test";        
button.Height = 17;

RadHostItem host = new RadHostItem(button);
host.MinSize = new Size(50, 0);
host.MaxSize = new Size(0, 17);
host.StretchVertically = false;

radRibbonBar1.QuickAccessToolBarItems.Add(host);