Lack of "dead time" tolerance between mouse-button press & mouse-button release for various menu pop-ups
Tested on Xfce 4.19.3 in a live session of Xubuntu 24.10
I'm aware there was a relatively large update between Xfce 4.19.3 and 4.19.5, but this issue has at least existed since Xfce 4.16.8 and actually seems to exist on a slew of other desktop environments (I actually first discovered this issue in Cinnamon) which initially made me think it was the fault of something upstream, but it occurs even on Qt-based desktop environments (particularly, KDE and LXQT); also possibly notable is that Gnome avoids the issue altogether by having menus either only appear on mouse button-release or by having a visual delay between mouse button-press and the actual menu being shown.
Simply put, Xfce seems to not have any "dead time" tolerance between the mouse button-press action and the mouse button-release action. This means that, in many menu-oriented situations, if you move your mouse in-between a mouse button-press and mouse button-release sequence that only lasts all of 100ms (not a typo) and only moved a single pixel, it will still be treated as if you held the button for a while, moved the cursor, and then released the mouse button, rather than the expected behavior of it being treated as just a stand-alone click.
In general, this results in a behavior that can make certain things feel overly sensitive whereby you must always make absolute sure to not move the cursor during the likes of a standard right-click to show a context menu (not shown in the video), left-clicking on a drop-down menu, or clicking on a panel item that has a built-in menu such as the "Notification Plugin".
It's notable however that Thunar's File, Edit, View, etc menus do not exhibit this behavior and actually does seem to include some sort of "dead time" tolerance that prevents this exact issue. Firefox also seems to incorporate such a thing, but this still seems to be something on a program-to-program basis as other programs will still do it (such as, not shown in the video, antimicrox)
Also, by definition, if you're someone that always does a mouse button-hold > move cursor > mouse button-release for various menus and such, then you would never run into this issue, but this is not at all natural muscle memory for me.
Video demonstration (note the left & right-click indicators in the bottom-right; you may also want to download the video and step frame-by-frame to see this ~100ms timeframe between mouse button-press and mouse button-release):