Whyzat? :P Do you even know why it has to make tooltips?
Yes I do. So that comparison tooltips can be shows for both ItemRefTooltip and GameTooltip at the same time. But in 3.2 they are adding three new comparison tooltips for ItemRefTooltip so why would you need to continue creating your own?
EQCompare is dead.
tekKompare won't need to create its own tooltips in 3.2.
Mirror is just a cheap tekKompare clone so if it got updated it wouldn't need to create its own tooltips in 3.2 either.
AtlasLoot should DIAF for using its own tooltip instead of GameTooltip.
Unless I'm mistaken, if you add the line on the first call, it adds the line directly below the "item" made by the recipe, which ends up in the middle of the tooltip instead of the end, most likely not what you want.
As shown in this image, if you blocked the second call, only the first "ItemLevel: 85" line would be shown.
You are mistaken. Mendeleev does post hooks of OnTooltipSetItem and OnTooltipCleared and it works perfectly when both the recipe and the item the recipe creates are in the local cache. I don't remember what happens when one isn't in the cache though, but if it does misbehave it will be correct the next time the tooltip is shown.
The top line in your screenshot is from the second call not the first.
Secondly, using the OnTooltipSetItem method means extra checking on every item tooltip you show, not that you will show a lot of tooltips very often, but the overhead is there. While the hooking-all-methods method is a one time thing on load.
Yes, thats just one addon, what about those that don't have one and you/your users would want support for it.
What are you smoking? The hooks are still called on every tooltip even if you use the hook-all-methods method.