Curse

First you should decide where to add effects from this spells. It seems they procs from "Imbue weapon" spells. If you want to attach to this spells you can search wowhead for their spell id's (like "Flametongue Weapon" http://www.wowhead.com/spell=8024 where id is 8024, then you should add to spells.lua string like "[118472] = 8024," where 118472 is spell id that actually did damage of healing, not BUFF, they can be different). But by adding effects to "Imbue weapon" you will have all damage/healing effects done between button's clicks (per 30-60 minutes).

Or if you want to add effect to spell that buffed by "imbue weapon" you can use "[118472] = 421," where 421 is "Chain Lightning".

There is "Howto" in description. I was not able to fill all spells for all classes and check at all levels for action buttons that casting another spell id. Of course you can still wait for DrDamage instead.

You can see example at http://www.wowinterface.com/downloads/info21766-LastEffect.html#comments how to fix such spells.

Checked with new mage alt, "Frostfire Bolt" works with standard Blizzard bars, shows last damage or avreage damage.

Oops (I have them in other addons, so not noticed). Will fix it in next version. About ButtonForge - I made similar in TinyExtraBars

Edit: reason - lot of addons like Bartender, Dominos etc simply reusing or rearranging Blizzard's action buttons. LastEffect made simple to use only action-based buttons. Addons like ButtonForge and TinyExtraBars much more complicated and using own buttons (not action based). In case of ButtonForge things even more complicated - each button is object with link to widget. It is not impossible, but will make addon much more complicated.

Addon logic changed to amount of damage/heal between button clicks. It helps to solve issue with channeled spells that looks like several independent casts in combat log. Also that required to make average mode.
Added optional "average" mode (see slash commands: type "/le" or "/LastEffect" in chat to see available). This mode suppose to show average of last 10 casts.

Possible issue: there is time between click and actual damage (depends from distance) and by casting nonstop sometime 2 casts can be count as 1. Can't find solution yet.

Feedback would be nice.

I was thinking about that. Average of 10-100 casts will require lot of time to manage data from previous casts (add new, reorder array and get average). Also by switching targets for example from boss to normal targets you will see proper results somewhere in 5 minutes (3 sec * 100 casts = 300 sec). So finally I was thinking about average from current and previous casts. Or maybe data per target, which is even more resource consuming.

Tooltips is what I disabled in DrDamage because I using keyboard to move (battlegrounds) + mouse to click buttons. And half of screen with tooltips I even can't read during combat was last thing I need. Also Recount (at cost of lags sometime) have much better statistics (shiny, colored, shaped).

However right now I'm away from growing potatoes for Tillers and took a break from WoW. So maybe later I will do something if I will feel something is missing or can be done better.

It works with Dominos (checked).