Keyboard Shortcut: Alt Overrides Ctrl/Shift+Alt

I’m trying to assign Ctrl+Alt as “Copy Selection” and Alt+Shift as “Intersect Selection”, just like Photoshop. However, as long as I assign Alt key as “Subtract Selection”, both Ctrl+Alt and Alt+Shift won’t work as intended.

The version I’m using is 1.2.25 (x64) and I’m running it on my Windows 10 laptop.