Attack support gems must be in weapon?

I am trying to use the Elemental Damage with Attacks Support gem with some skill (either Glacial Hammer, Infernal Blow, Molten Strike, etc). When I had the gem linked with an attack skill in my armor, I noticed that there was no change in the skill stats on the character page when I took the Elemental Damage with Attacks Support gem in and out. It also did not show the icon "W" on the skill or change the mana cost as expected.

It took some messing around to realize that all of the changes I would expect from the supported skill would only appear when I had the skill and support gem linked in a weapon (see dps update, "W" symbol, mana cost). I tried the same, in and out of armor, with the Added Fire Damage Support gem and found that changes only appeared when the gem was linked with an attack in the weapon.

Is this how the gems are supposed to behave? There is no indication of this in the tooltips of the gems themselves. I would expect the support gem to add damage to the supported skill, even if they were linked in another item. Are the skill stats just not updating in the character screen when the gems are linked elsewhere? I haven't been able a controlled way to test the skill damage.

No, that's not how it's meant to work (and, as far as I know, how it does work).

Could you go here, let us see your characters, and tell us which one you've been testing on?

i'm dumb. i was using full plate and the sockets looked like they were linked because of the item graphic but weren't.

Yeah... they should probably change that. >.>

Well done on figuring it out!