I just discovered an interesting bug (or feature) of the hotkeys for Skills in D2R. I found this bug (or feature) on two of my Sorceresses on Offline Single Player mode - I’m not sure if these specifics matter for this bug (or feature). I think this is likely a bug though, since it requires reloading the game for it to show up. I also don’t know if this is a D2R-only bug or a bug in the original D2, since I never noticed it in the original D2.
If other people can’t reproduce what I found here, then it’s probably a bug with my game or my system that runs it.
The bug seems to be the following based on my tests:
(x, y are the numbers for the Skill Hotkeys.)
If you set the Skill x Hotkey to a skill, then if you reassign the skill (for the same mouse button) to the Skill y Hotkey, then before you quit the game, the skill would be shown as having the Skill y Hotkey and is indeed activated by the Skill y Hotkey and not by the Skill x Hotkey. But if you quit to the main menu and reload the game, the skill would be shown as having the Skill x Hotkey if x < y and the Skill y Hotkey if x > y, but both the Skill x Hotkey and the Skill y Hotkey can be used to activate the skill. Now (after reloading the game) if for example x<y, in which case the button is shown to have the Skill x Hotkey, if you reassign the Skill x Hotkey to a different skill for the same mouse button, the original skill’s hotkey would be changed to the Skill y Hotkey.$
So basically the lower numbered Skill Hotkey “covers” the higher numbered Skill Hotkey in terms of what the game shows, but after reloading the game, both of the hotkeys work.
Similarly, if you have one of your skills set to the Skill x Hotkey for your e.g. right mouse button, if this skill can also be activated by your left mouse button, you can set this skill to be a different hotkey for your left mouse button. Assume that you set the skill to be activated by the Skill y hotkey for the left mouse button. Then before you quit the game, the hotkey for the skill is simply reset to the Skill y Hotkey and can no longer be activated by the Skill x Hotkey. But once you reload the game, you’ll find that this skill is assigned to the Skill y Hotkey on your left mouse button and the Skill x Hotkey on your right mouse button - you can now use this skill on both your left and right mouse buttons with different hotkeys.
Footnote:
$ If you reassign the Skill x Hotkey to a new skill (which can be the same skill) for the other mouse button, then before reloading the game everything behaves normally as expected, but after reloading the game, the original skill for the original mouse button would have the Skill y Hotkey, and the new skill for the other mouse button would have the Skill x Hotkey - the skill can now be activated by both mouse buttons with different hotkeys.
For examples:
My Q is the hotkey for Skill 1 and my D is the hotkey for Skill 8.
For any skill that is already set to have the Hotkey Q for the right mouse button, if I reset it to D (for the right mouse button), then before I quit the game, the skill would be shown as having the Hotkey D and is indeed activated by D and not by Q - the expected normal behavior.
But once I quit and reload the game, the hotkey that is shown on top of the skill (for the right mouse button) would be changed back to Q, and interestingly, if I press D, the skill would still be activated - now the skill can be activated by both Q and D with the right mouse button even though the hotkey that the game shows is just Q. Hence you can assign two hotkeys to the same skill for the right mouse button.
Similarly, if you have one of your skills set to Q for your right mouse button, if this skill can also be activated by your left mouse button, you can set this skill to be a different hotkey for your left mouse button, for example D. Assume that you indeed set the skill to be activated by D for the left mouse button. Then before you quit the game, the hotkey for the skill is simply reset to D and can no longer be activated by Q - the expected normal behavior. But once you reload the game, you’ll find that this skill is assigned to D on your left mouse button and Q on your right mouse button - you can now use this skill on both your left and right mouse buttons with different hotkeys.
You can see a picture of my Frozen Orb being assigned to both Q and D here:
https://www.reddit.com/r/diablo2/comments/qhhlop/skill_hotkey_double_assignment_bug_or_feature/
This is actually a helpful feature, whether it is a bug or not.