Oh, it's easy, though the hotbar's effects vary sharply according to the weapon. As you see here, I have this setup with guns:
First you get two weapons. (For this case only)
Then you macro them on the hotbar.
Then when you try to click or press 2, this happens.
Now, this only happens from time to time, between reboots for some reason.
And the effects of the hotbar varies from:
1- 'No attack', often in melee weapons.
2- 'Jackhammer Range' on all firearms.
3- This varies from player to player, the lucky players use said melee weapon attacks, and they activate, and when it does, the attack either doesn't count Fleur, does Magic Damage instead of Physical Damage, or both.
By the way, this only happens with the main hand's attack, I didn't see off-hand having any issues but I might be wrong.
It's like Kameron said once, it's not something 'precise' to pinpoint because the effects are way too random. But judging by the firearm's difference, it feels like something is out of place.
(My expectation now)
Like for example, using a fist weapon doesn't do anything because it's trying to perform a melee attack with a 'bow type' attack, and fists don't have a projectile, so it fails.
Then the magic damage comes from a 'tome type' being used instead of melee, for damage.
Anything beyond this, I have absolute zero idea since I didn't code anything for the game and I don't know how anything works, besides the way BYOND's updates always tend to fuck up the code. *shrug*