Keybindings behave inconsistently/unexpectedly

I can use the mouse wheel with Ctrl + Shift to either Change Frame (as is the default keybinding) or to Change Layer and it works as expected, but using Ctrl + Alt for those actions behaves inconsistently and seems to jump between frames/layers unpredictably.

Steps to recreate:

  1. Set “Change Layer” to both Mouse Wheel action “Ctrl + Alt” and “Ctrl + Shift”
  2. Create a new sprite
  3. Press Shift+N twice to create layers 2 and 3.
  4. Scroll with mouse wheel while holding Ctrl + Alt, it only changes between layers 2 and 3, while Ctrl + Shift changes between all three.

That’s it. If you create an additional layer #4 afterwards and try scrolling again, Ctrl+Alt will switch between #4 and #2 instead.

Version: Steam (tested on both Ubuntu and Windows)