This probably related to this change that @Cattlesquat put into V3.7.0:
11919: Allow DEL/BACKSPACE to be mapped as a hotkey
(It’s not, the behaviour is identical in v3.6.19, for me at least).
I notice in any such field (trait or component), that I see Ctrl+ when I press Ctrl+H, keeping it pressed. However, the “H” is added when I release the key. Is that not what you’re seeing @shilinski. If not, I’m using MacOS. What are you using? This is different from other control keystrokes, and probably a “feature” of being able to translate the backspace into a Vassal keystroke symbol.
Could this be an issue (or intentional) to do with this v3.7.1 change, @Brent_Easton ?
12670: Prevent essential components being accidentally deleted
I’m using windows, and I add that this happens only with control h. It doesn’t happen with any other letter, at least for those I’ve tried. I haven’t gone down the rabbit hole on this because I’m working on a module. Maybe I’ll try to characterize it better when I return home.