Happens on:
``` 10:34:28: Geany INFO : Geany 1.38 (git >= e027e240), en_AU.UTF-8 10:34:28: Geany INFO : GTK 3.24.20, GLib 2.64.6 10:34:28: Geany INFO : OS: Linux Mint 20 (ulyana) ```
if:
1. the right mouse button is held not clicked 2. while its held the cursor moves to the top menu item (undo) due to shakey hands, cosmic winds or something else 3. undo happens when right mouse button is released
This is of course how its meant to work when mouse down is separate from mouse up, ie the time between is greater than the mouse click period.
If the click speed is set faster than the menu animation and the user or GTK waits for the menu to appear then the mouse operation will be seen as a separate "down" and "up" which makes the menu execute whatever operation is selected. So if the cursor moves while waiting it can select the nearest menu item. Hence changing the theme to remove animation and making the menu appear before the click timeout "solves" the problem. Its possible also that the different theme has more of a border on the menu that means the cursor has to be moved further, stopping it hitting the undo item.
So its not really a "bug" as such, everything happening is meant to happen, just that a combination of timings and theme values that makes it easy to make an action happen when a user didn't expect it.
AFAIK the themes for macosx are delivered as they come without Geany changing anything, I guess its up to @techee if supporting modifications is acceptable.