For me last couple trading session at open my charts simply dont work/update...sometimes for 30 seconds or more. Once they never worked and had to restart and missed the opening action
The issue I have with the TWS Charts (and it's been a TWS problem for ever) is they don't maintain the proper "Time Period". If I set a chart to display "8 Hours/5 minutes" (which is supposed to display a 5 minute chart for the last 8 hours), it does not maintain the 8 hour window. After a while, it will only display a 4 hour window. You have to continually toggle time periods to get the chart to display properly and even then, it doesn't display the entire time period. Same thing when looking at IPOs. If I set a 1 minute chart for 4 hours (or even 2 hours), as candles are drawn, the chart does not maintain the proper time period and does not even display all candles even from 15 minutes ago. Again, you have to constantly toggle the time period to view all candles from the start of an IPO only 15 minutes ago.