the symbol (last I checked) is CBOE:$RUI and it is in the built in index panel. If you have the index panel open, then you should NOT have that symbol in the portfolio (it would cause a conflict)
The other common cause for data not coming in is if the symbol in question is not getting real time data returned. If IB requires a subscription for the given index and you don't have it, it will show delayed in TWS, but not get any data in QT. QT only subscribes to the real-time data in IB.
Jerry