Currently, keyboard shortcuts are customizable. Mouse actions are not.
Add the ability to customize what each mouse event (left/middle/right click) does and where depending on the keyboard modifier pressed (none/cmd/ctrl/alt/shift/super).
This is quite a broad FR and encompasses several others:
When I filed Custom hotkey for Open link under cursor to the right not working - #3 by WhiteNoise it didn’t occur to me that there was a distinction between hotkeys and mouse events with keyboard modifiers (because the modifiers were the same as the hotkey minus “Enter”), even though they are, as you say, different things. I mention it in case it helps with the UX for this FR, if it ever gets done.
Although this FR far more encompassing than I would have asked for (I just want to be able to make it so Command-click opens a note in a new pane instead of a new tab), if this gives me what I need, yes please!
I would love to use scroll wheel to cycle through tabs. If scroll up / scroll down were assignable in hot keys, that could be used along with the Ctrl+Tab options.
Oh, but I guess it would kinda break scrolling. The scroll wheel to cycle tabs typically is when the mouse is hovered over the tabs (see e.g. google chrome). But you can currently Ctrl+Tab to cycle tabs independent of cursor location.