XApp Status Applet - border prevents use of Magic Corner

[quiddity-wp]

Hallo! I have the XApp Status Applet positioned at the right-edge of my panel.
It has the Volume Control on the right-most side.
I want to be able to throw my mouse-cursor into that corner, and immediately be able to scroll-wheel the volume [up/down].

Currently, there is a (2px?) border on the right of the XApp Status Applet which prevents this from working.

I.e. If I right-click that corner, then instead of giving me the expected Volume options ("Mute", "Sound preferences") it gives me the XApp Status Applet options:

Request: Is there a workaround that I/we can use, to remove the right-border on this feature?

Prior unsuccessful attempts/research:

• I tried changing all the options given via "Control Panel -> Appearance -> Theme-> Customize"
• I tried using the answer given here: how to disable 1-pixel panel border added in commit 8c49f552? mate-desktop/mate-themes#232
• I tried using the standalone "Volume applet" (seems to have the same problem?)
• I tested other applets, and they do Not all have the same problem (e.g. "Weather Report" works as desired if placed in the corner), therefor this is probably not a Mate-desktop bug (?).
• This is all on a brand new install. Mint 20.2 Uma 64-bit, MATE 1.24.0
• This worked as desired in Mint 19.1

Much thanks!

(p.s. The "Magic Corner" term is taken from https://en.wikipedia.org/wiki/Fitts%27s_law#Implications_for_UI_design )