Thinkorswim Custom Watchlist Columns Not Recalculating Premarket

[ronbla]

Thinkorswim custom watchlist columns not recalculating premarket — quotes update normally

I'm trying to determine whether I'm seeing a Thinkorswim limitation/throttling issue with custom watchlist columns during extended-hours trading.

I have a FAST watchlist with about 29 symbols and four custom thinkScript columns:

• CONF-15 — 15-minute calculation
• T-INT F V2 — intraday calculation
• T-INT-F 5M — 5-minute calculation
• JOE-F V2 — composite calculation

During yesterday's regular trading session, these columns updated normally and reacted to market movement.

This morning during premarket, however, I noticed something very different.

The Last/Bid/Ask fields continue updating normally, but all four custom thinkScript columns can remain completely unchanged for 30+ minutes.

For example, SOXL remained:

CONF-15 = 54
T-INT F V2 = 17
T-INT-F 5M = 20
JOE-F V2 = 0

Those values stayed identical while SOXL's Bid/Ask moved substantially and multiple 5-minute bars passed.

I tried several things to force recalculation:

• Switched to another watchlist and back
• Added a column to the watchlist
• Detached the watchlist
• Exported the watchlist to Excel
• Completely exited and restarted Thinkorswim

None caused the populated custom-column values to recalculate.

Interestingly, when I created a new custom script and then deleted it, several symbols suddenly displayed "loading" across all four custom columns, while Last/Bid/Ask remained populated. Other symbols continued displaying their previous calculated values.

That makes me wonder whether TOS maintains a separate calculation queue/cache for custom quotes and throttles those calculations during extended hours.

Questions:

1. Are custom watchlist thinkScript columns known to recalculate less frequently or be throttled during premarket/extended-hours sessions?
2. Is there a command or reliable method to force TOS to recalculate all custom quote columns?
3. Can a 5-minute custom quote remain unchanged even though several new 5-minute extended-hours bars have completed?
4. Is there anything specific that must be included in thinkScript code to ensure custom quote calculations use and refresh from extended-hours data?
5. Could having four custom columns across roughly 29 symbols be enough to trigger TOS calculation throttling?

The especially puzzling part is that the same watchlist and scripts worked normally during the regular market session yesterday.

I'm trying to determine whether this is expected TOS behavior before changing the scripts themselves.

Any insight from people who have worked extensively with custom watchlist columns and extended-hours data would be appreciated.