Considering that Claws Mail stops processing next filter rules if there is a match for a rule with a move/stop action, it would be useful to have visual indication for those particular rules (and/or for those which don't move/stop). For example a different text color/background/icon for those rules. This would be helpful to assign correct order of rules easier.
The code's term is "final action". There are currently only three of them -- STOP & DELETE, for which "no more processing" seems obvious, and MOVE. Up until 3.16 MARK_AS_SPAM was also a final action, but this has changed in 3.17. This is defined in a function named "filtering_is_final_action()" in the file filtering.c. Given that the set of non-obviously-final actions includes only one action, I think that adding code to visually mark final actions differently is a bit of an overkill. That said, AFAIK the whole issue is not documented anywhere, and adding this documentation might be useful.
> I think that adding code to visually mark final actions differently is a bit of an overkill. I don't see why. To me it is an overkill to look at a long line of text (for more complex rules) in which even the action is not visually separated from the condition. A good UI combines function with visuals and currently nothing gives a visual hint about what is done and what is the effect of it (in the context of this whole suggestion)
I guess a small red "X" icon, or something similar, next to the rule name could work, especially with a tooltip that says what it means.
Sounds good. Another thing (in the context of my previous reply): It would be good also to have a visual separation between the action and the condition on the line of the rule. For example: the text of the action can be different color (or bold), e.g. from matchcase "watever@example.com" [*style*]move "...somewhere"[/*style*] Perhaps this should be in a separate bug. Please let me know if I should file one or it can be done at once for both things.