wx w/ many channel breaks on mode change

[gnodar01]

Screen.Recording.2025-05-29.at.10.36.13.AM.mov

It seems there was a regression introduced where upon changing from composite mode to grayscale mode the LUT for "None" is gone. Then upon changing back to composite, all LUTs are not displayed, despite having their display boxes enabled.

Seems this bug was introduced in the last few commits introduced in #195 by @tlambert03 when cleaning up my otherwise messy state logic. Totally my fault, since this is actually what that the commented out code in the tests was supposed to test for, but I couldn't figure out how to simulate channel mode changes so I never ended up completing it.

[tlambert03]

Sorry!! 😣

[gnodar01]

🤣 No worries! Mostly my fault, plus our use of this won't be in production for like a year, so zero consequences for a bug here and there.