When trying to enter a new custom filter where there's user prompts in the code in the Session Browser in Toad for Oracle; for example:
When testing it in the Filter window, the following error occurs:
ORA-00936: missing expression
In the Session Browser, let it pull all SIDs in the browser and focus the cursor on the SID field. Then type in the desired SID as Toad will perform an incremental search in the grid as the user types.